Cabot Energy Regulatory News (CAB)

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARESi 1. Identity of the issuer or the underlying issuerof existing shares to which voting rights are Northern Petroleumattached:ii 2. Reason for the notification (please tick the appropriate box or boxes): An acquisition or disposal of voting rights

X

An acquisition or disposal of qualifying financial instruments which may resultin the acquisition of shares already issued to which voting rights are attached

An acquisition or disposal of instruments with similar economic effect toqualifying financial instruments An event changing the breakdown of voting rights Other (please specify): 3. Full name of person(s) subject to the Cavendish Asset Management Ltdnotification obligation:iii 4. Full name of shareholder(s) n/a (if different from 3.):iv 5. Date of the transaction and date onwhich the threshold is crossed or 17/05/2013reached: v 6. Date on which issuer notified:

20/05/2013

7. Threshold(s) that is/are crossed or 5%reached: vi, vii

Embargoed for immediate release on 21 May 2013

Northern Petroleum Plc ("Northern" or "the Company") Notification of Shareholding 8. Notified details: A: Voting rights attached to shares viii, ix Class/ Situation previous Resulting situation after the triggering transactiontype of to the triggeringshares transaction if Number Number Number Number of voting % of voting rightspossible of of of shares rights xusing Shares Votingthe ISIN RightsCODE Direct Direct xi Indirect xii Direct Indirect Sedol:B0D47T6 4,737,451 4,737,451 5,278,683 5,278,683 - 5.5% -(ordinaryshares) B: Qualifying Financial Instruments Resulting situation after the triggering transaction Type of Expiration Exercise/ Number of voting % of votingfinancial date xiii Conversion Period xiv rights that may be rightsinstrument acquired if the instrument is exercised/ converted. n/a C: Financial Instruments with similar economic effect to Qualifying FinancialInstruments xv, xvi Resulting situation after the triggering transaction Type of Exercise price Expiration Exercise/ Number of voting rights % of votingfinancial date xvii Conversion instrument refers to rights xix, xxinstrument period xviii Nominal Deltan/a Total (A+B+C) Number of voting rights Percentage of voting rights 5,278,683 5.5%

9. Chain of controlled undertakings through which the voting rights and/or thefinancial instruments are effectively held, if applicable: xxi

Proxy Voting: 10. Name of the proxy holder: n/a 11. Number of voting rights proxy holder will cease to hold: 12. Date on which proxy holder will cease to hold voting rights: 13. Additional information: 14. Contact name: Paul Mumford (Fund Manager) Deborah Banister (Back Office) 15. Contact telephone number: 020 8810 8042 (Paul) 020 8991 8995 (Deborah) ---ENDS---

For further information please contact:

Northern Petroleum Plc Tel: +44 (0) 20 7469 2900Derek Musgrove, Managing DirectorNick Morgan, Finance Director Notes to Editors: Northern is a full cycle oil and gas company currently holding numerouslicences in a number of low risk areas and is continuing with its strategy ofadding and securing value for shareholders as it engages with projects at allstages of the E&P value chain.

Comprehensive information on Northern and its oil and gas operations, includingall press releases, annual reports and interim reports are available fromNorthern's website: www.northpet.com