<SEC-DOCUMENT>0001140361-12-019608.txt : 20120405
<SEC-HEADER>0001140361-12-019608.hdr.sgml : 20120405
<ACCEPTANCE-DATETIME>20120405171540
ACCESSION NUMBER:		0001140361-12-019608
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20120403
FILED AS OF DATE:		20120405
DATE AS OF CHANGE:		20120405

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			AMARIN CORP PLC\UK
		CENTRAL INDEX KEY:			0000897448
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			X0
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		FIRST FLOOR, BLOCK 3, THE OVAL,
		STREET 2:		SHELBOURNE ROAD, BALLSBRIDGE
		CITY:			DUBLIN
		STATE:			L2
		ZIP:			00000
		BUSINESS PHONE:		353 1 6699 020

	MAIL ADDRESS:	
		STREET 1:		FIRST FLOOR, BLOCK 3, THE OVAL,
		STREET 2:		SHELBOURNE ROAD, BALLSBRIDGE
		CITY:			DUBLIN
		STATE:			L2
		ZIP:			00000

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	AMARIN PHARMACEUTICALS PLC
		DATE OF NAME CHANGE:	20000201

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ETHICAL HOLDINGS PLC
		DATE OF NAME CHANGE:	19930322

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Abingworth LLP
		CENTRAL INDEX KEY:			0001397144
		STATE OF INCORPORATION:			X0
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	333-176897
		FILM NUMBER:		12746459

	BUSINESS ADDRESS:	
		STREET 1:		38 JERMYN STREET
		CITY:			LONDON
		STATE:			X0
		ZIP:			SW1Y 6DN
		BUSINESS PHONE:		44 (0)20 7534 1500

	MAIL ADDRESS:	
		STREET 1:		38 JERMYN STREET
		CITY:			LONDON
		STATE:			X0
		ZIP:			SW1Y 6DN
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0305</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-04-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000897448</issuerCik>
        <issuerName>AMARIN CORP PLC\UK</issuerName>
        <issuerTradingSymbol>AMRN</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001397144</rptOwnerCik>
            <rptOwnerName>Abingworth LLP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>PRINCE HOUSE</rptOwnerStreet1>
            <rptOwnerStreet2>38 JERMYN STREET</rptOwnerStreet2>
            <rptOwnerCity>LONDON</rptOwnerCity>
            <rptOwnerState>X0</rptOwnerState>
            <rptOwnerZipCode>SW1Y 6DN</rptOwnerZipCode>
            <rptOwnerStateDescription>UNITED KINGDOM</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Ordinary Shares, 50 pence par value per share</value>
            </securityTitle>
            <transactionDate>
                <value>2012-04-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2300000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>11.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5607509</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Notes</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Abingworth LLP (the &quot;Reporting Person&quot;) is the investment manager to a number of investment funds that include Abingworth Bioventures V L.P. (&quot;ABV V&quot;), Abingworth Bioventures V Co-Invest Growth Equity Fund LP (&quot;AGE&quot;), and Abingworth Bioequities Master Fund Limited (&quot;ABE,&quot; and collectively with ABV V and AGE, the &quot;Abingworth Funds&quot;).  On April 3, 2012, ABV sold an aggregate of 1,000,000 ordinary shares, 50 pence par value per share, of Amarin Corporation plc (&quot;Ordinary Shares&quot;), AGE sold an aggregate of 1,000,000 Ordinary Shares, and ABE sold an aggregate of 300,000 Ordinary Shares.</footnote>
        <footnote id="F2">The Reporting Person may be deemed to beneficially own the Ordinary Shares reported herein indirectly through the Abingworth Funds.  The Reporting Person's interest in the securities reported herein is limited to the extent of its pecuniary interest, if any, in the Abingworth Funds.  This report shall not be deemed an admission that the Reporting Person, each Abingworth Fund or any other person is the beneficial owner of the securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ John Heard, Authorized Signatory</signatureName>
        <signatureDate>2012-04-05</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
