UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                  SCHEDULE 13D

                           (Amendment No. __________)

                    UNDER THE SECURITIES EXCHANGE ACT OF 1934



                              AMARIN CORPORATION PLC
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                                (Name of Issuer)


                          ORDINARY SHARES, 5p PAR VALUE
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                         (Title of Class of Securities)


                                  023111 10 7
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                                 (CUSIP Number)



                                  David J. Doyle
                         Amarin Investment Holding Limited
                          Clarendon House, 2 Church Street
                                  Hamilton,HM11 Bermuda
                                 1 441 295 1422
                                
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                   (Name, Address and Telephone Number of Person
                 Authorized to Receive Notices and Communications)




                                 OCTOBER 6, 2004
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             (Date of Event which Requires Filing of this Statement)


If the filing person has previously filed a statement on Schedule 13G to report
the acquisition that is the subject of this Schedule 13D, and is filing this
schedule because of Sections 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check
the following box. [   ] 

Note: Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See Section 240.13d-7 for other
parties to whom copies are to be sent.



* The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be
deemed to be "filed" for the purpose of Section 18 of the Securities Exchange
Act of 1934 ("Act") or otherwise subject to the liabilities of that section
of the Act but shall be subject to all other provisions of the Act (however,
see the Notes).

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CUSIP NO.  023111 10 7              SCHEDULE 13D              PAGE 2 OF 8 PAGES

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1.                NAMES OF REPORTING PERSONS/I.R.S. IDENTIFICATION
                  NOS. OF ABOVE PERSONS (ENTITIES ONLY)

                  AMARIN INVESTMENT HOLDING LIMITED
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2.                CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP    (A) [ ]
                  (SEE INSTRUCTIONS)                                  (B) [ ]
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3.                SEC USE ONLY


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4.                SOURCE OF FUNDS (SEE INSTRUCTIONS)

                  AF

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5.                CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT
                  TO ITEMS 2(d) OR 2(e)                                   [ ]


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6.                CITIZENSHIP OR PLACE OF ORGANIZATION

                  BERMUDA
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                               7.     SOLE VOTING POWER

                                      7,371,210
   NUMBER OF                  --------------------------------------------------
    SHARES                     8.     SHARED VOTING POWER
 BENEFICIALLY
   OWNED BY                           0
    EACH                      --------------------------------------------------
  REPORTING                    9.     SOLE DISPOSITIVE POWER
   PERSON
    WITH:                             7,371,210
                              --------------------------------------------------
                               10.     SHARED DISPOSITIVE POWER

                                      0
--------------------------------------------------------------------------------
11.                AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

                  7,371,210
--------------------------------------------------------------------------------
12.               CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
                  CERTAIN SHARES (SEE INSTRUCTIONS)                     [  ]
--------------------------------------------------------------------------------
13.               PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)

                  19.6%
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12.               TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

                  CO
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CUSIP NO.  023111 10 7              SCHEDULE 13D              PAGE 3 OF 8 PAGES

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1.                NAMES OF REPORTING PERSONS/I.R.S. IDENTIFICATION
                  NOS. OF ABOVE PERSONS (ENTITIES ONLY)

                  THOMAS G. LYNCH
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2.                CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP    (A) [ ]
                                                                      (B) [ ]
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3.                SEC USE ONLY

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4.                SOURCE OF FUNDS (SEE INSTRUCTIONS)

                  PF

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5.                CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT
                  TO ITEMS 2(d) OR 2(e)                                   [ ]

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6.                CITIZENSHIP OR PLACE OF ORGANIZATION

                  UNITED KINGDOM
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                               7.     SOLE VOTING POWER

                                      7,371,210
   NUMBER OF                  --------------------------------------------------
    SHARES                     8.     SHARED VOTING POWER
 BENEFICIALLY
   OWNED BY                           0
    EACH                      --------------------------------------------------
  REPORTING                    9.     SOLE DISPOSITIVE POWER
   PERSON
    WITH:                             7,371,210
                              --------------------------------------------------
                               10.     SHARED DISPOSITIVE POWER

                                      0
--------------------------------------------------------------------------------
11.                AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

                  7,371,210
--------------------------------------------------------------------------------
12.               CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES
                  CERTAIN SHARES*                                           [ ]
--------------------------------------------------------------------------------
13.               PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

                  19.6%
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14.               TYPE OF REPORTING PERSON*

                  IN

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CUSIP NO.  023111 10 7              SCHEDULE 13D              PAGE 4 OF 8 PAGES
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ITEM 1.  SECURITY AND ISSUER

      (a) Security and Issuer: This statement relates to the ordinary shares, 5p
par value, of Amarin Corporation plc. The principal offices of the issuer of
such securities is located at 7 Curzon Street, London, United Kingdom W1J 5HG

           ---------------------------------------------------------

ITEM 2.  IDENTITY AND BACKGROUND

      (a) Name:

       This statement is filed on behalf of each of the following persons:

          (i)  Amarin Investment Holding Limited

          (ii) Thomas G. Lynch
                                

      (b) Residence or business address:

          (i)  Amarin Investment Holding Limited
               Clarendon House
               2 Church Street
               Hamilton,HM 11 Bermuda
 
          (ii) Thomas G. Lynch
               c/o Amarin Corporation plc
               7 Curzon Street
               London, United Kingdom W1J 5HG


      (c) The principal occupation of Thomas G. Lynch is as Chairman and a non-
          executive Director of Amarin Corporation plc, located at 7 Curzon
          Street, London, United Kingdom W1J 5HG.  The principal business of
          Amarin Corporation plc is the development of pharmaceutical compounds
          for the treatment of neurological diseases.

          The principal occupation of David J. Doyle is as director of Amarin
          Investment Holding Limited, located at Clarendon House, 2 Church
          Street, Hamilton, Bermuda. The principal business of Amarin Investment
          Holding Limited is investment.


     (d) During the past five years, none of the reporting persons, or any other
     person named in Item 2(c), has been convicted in a criminal proceeding
     (excluding traffic violations or similar misdemeanors).


     (e) During the past five years, none of the reporting persons, or any other
     person named in Item 2(c), was a party to any civil proceeding of a
     judicial or administrative body of competent jurisdiction as a result of
     which such reporting person (or other person) was or is subject to a
     judgment, decree or final order enjoining future violations of, or
     prohibiting or mandating activities subject to, federal or state securities
     laws or finding any violation with respect to such laws.

               

      (f) Citizenship:

          (i) Amarin Investment Holding Limited is an exempted company limited
              by shares, formed under the laws of Bermuda                      

          (ii) Thomas G. Lynch is a citizen of the United Kingdom
               David J. Doyle is a citizen of Bermuda


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CUSIP NO. 023111 10 7               SCHEDULE 13D              PAGE 5 OF 8 PAGES
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ITEM 3. SOURCE AND AMOUNT OF FUNDS OR OTHER CONSIDERATION

     On September 30, 2004, in a privately negotiated transaction, Amarin
     Investment Holding Limited entered into an agreement to purchase 4,653,819
     American Depositary Receipts representing 4,653,819 ordinary shares of
     Amarin Corporation plc, together with warrants exercisable at any time
     after May 31, 2005 into 500,000 ordinary shares of Amarin Corporation
     plc, and $5 million in aggregate principal amount of secured loan notes
     issued by Amarin, for an aggregate consideration of $6,500,000. The source
     of these funds was working capital of Amarin Investment Holding Limited,
     which working capital was obtained through equity investment by its sole
     shareholder, Thomas G. Lynch, from his personal funds.  This transaction
     closed on October 6, 2004.

     On October 7, 2004 Amarin Investment Holding Limited converted $3 million
     in principal amount of secured loan notes of Amarin Corporation plc into
     2,717,391 ordinary shares of Amarin Corporation plc.


                       ------------------


ITEM 4.   PURPOSE OF TRANSACTION

     Amarin Investment Holding Limited entered into the transactions described
     above for general investment purposes.

     None of the reporting persons, nor any other person named in Item 2(c),
     has any plans or proposals which relate to or would result in: (a) the
     acquisition by any person of additional securities of the issuer, or the
     disposition of securities of the issuer; (b) an extraordinary corporate
     transaction, such as a merger, reorganization or liquidation, involving the
     issuer or any of its subsidiaries; (c) a sale or transfer of a material
     amount of assets of the issuer or any of its subsidiaries; (d) any change
     in the present board of directors or management of the issuer, including
     any plans or proposals to change the number or term of directors or to fill
     any existing vacancies on the board; (e) any material change in the present
     capitalization or dividend policy of the issuer; (f) any other material
     change in the issuer's business or corporate structure; (g)changes in the
     issuer's charter, bylaws or instruments corresponding thereto or other
     actions which may impede the acquisition of control of the issuer by any
     person; (h) causing a class of securities of the issuer to be delisted from
     a national securities exchange or to cease to be authorized to be quoted in
     an inter-dealer quotation system of a registered national securities
     association; (i) a class of equity securities of the issuer becoming
     eligible for termination of registration pursuant to Section 12(g)(4) of
     the Securities Exchange Act of 1934; or (j) any action similar to any of
     those enumerated above.



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CUSIP NO. 023111 10 7               SCHEDULE 13D              PAGE 6 OF 8 PAGES
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ITEM 5.  INTEREST IN SECURITIES OF THE ISSUER



       Amarin Investment Holding Limited:

     (a) Amount Beneficially Owned: 7,371,210 ordinary shares representing 19.6%
     of the outstanding ordinary shares. 
                                    
     (b) Number of shares as to which such person has:

       (i)   sole power to vote or to direct the vote: 7,371,210
                                                        
       (ii)  shared power to vote or to direct the vote: 0
                                                          
       (iii) sole power to dispose or to direct the disposition: 7,371,210
                                                                      
       (iv) shared power to dispose or to direct the disposition: 0
 
       Thomas G. Lynch:

     (a) Amount Beneficially Owned: 7,371,210 ordinary shares, representing
     19.6% of the outstanding ordinary shares. 
                                    
     (b) Number of shares as to which such person has:

       (i)   sole power to vote or to direct the vote: 7,371,210
                                                        
       (ii)  shared power to vote or to direct the vote: 0
                                                          
       (iii) sole power to dispose or to direct the disposition: 7,371,210
                                                                      
       (iv) shared power to dispose or to direct the disposition: 0

     (c) There have been no reportable transactions with respect to the ordinary
     shares of the issuer within the last 60 days by any of the reporting
     persons except for the acquisition of beneficial ownership being reported
     on this Schedule 13D.

     (d) Amarin Investment Holding Limited has the right to receive all
     dividends on the ordinary shares.

     (e) Not applicable.
 
           ---------------------------------------------------------

 ITEM 6.   CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS
           WITH RESPECT TO SECURITIES OF THE ISSUER

     Thomas G. Lynch has entered into a lockup agreement with Belsay Limited
pursuant to which he will not dispose of or agree to dispose of any ordinary
shares for a period of six months from October 8, 2004.  Belsay Limited is a
former shareholder of Laxdale Limited, a company which has recently been
acquired by Amarin Corporation plc.

           ---------------------------------------------------------

ITEM 7.   MATERIAL TO BE FILED AS EXHIBITS

     Exhibit          Title

        A             Joint Filing Agreement





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CUSIP NO. 023111 10 7               SCHEDULE 13D              PAGE 7 OF 8 PAGES
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                                    SIGNATURES

After reasonable inquiry and to the best of my knowledge and belief,
I certify that the information set forth in this statement is true,
complete and correct.



October 27, 2004

AMARIN INVESTMENT HOLDING LIMITED

By: /s/ David J. Doyle
-------------------------------------

David J. Doyle, Director
-------------------------------------
NAME/TITLE


October 27, 2004

/s/ Thomas G. Lynch
-------------------------------------

Thomas G. Lynch
-------------------------------------
NAME 





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CUSIP NO. 023111 10 7               SCHEDULE 13D              PAGE 8 OF 8 PAGES
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                                    EXHIBIT A
                             JOINT FILING AGREEMENT

The undersigned hereby agree that the statement on Schedule 13D with respect to
the ordinary shares of Amarin Corporation plc, dated as of October 27, 2004
is, and any amendments thereto signed by each of the undersigned shall be, filed
on behalf of each of us pursuant to and in accordance with the provisions of
Rule 13d-1(k) under the Securities Exchange Act of 1934.

Dated: October 27, 2004

AMARIN INVESTMENT HOLDING LIMITED

By: /s/ David J. Doyle
    -------------------------------------
    Name: David J. Doyle
    Title: Director


Dated: October 27, 2004


/s/ Thomas G. Lynch
-------------------------------------
Thomas G. Lynch