Holding(s) in Company

TR-1: Notifications of Major Interests in Shares

Identity of the issuer or the underlying issuer of existing shares to which voting rights are attached:

Tullow Oil PLC

Reason for notification (yes/no)

An acquisition or disposal of voting rights

yes

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

no

An event changing the breakdown of voting rights

no

Other (please specify):

Movement in Direct holding only

yes

Full name of person(s) subject to notification obligation:

Standard Life Investments Ltd

Full name of shareholder(s) (if different from 3):

Vidacos Nominees

Date of transaction (and date on which the threshold is crossed or reached if different):

3 March 2009

Date on which issuer notified:

5 March 2009

Threshold(s) that is/are crossed or reached:

3%

Notified Details

Voting rights attached to shares

Class/type of share If possible use ISIN code

GB0001500809

Situation previous to the triggering transaction

Number of shares

Number of voting rights

24,213,689

24,213,689

Resulting situation after the triggering transaction

Number of shares

Number of voting rights

Percentage of voting rights

Direct

Indirect

Direct

Indirect

below 3%

below 3%

below 3%

below 3%

below 3%

Financial Instruments

Resulting situation after the triggering transaction

Type of financial instrument

Expiration date

Exercise/ conversion period/date

No. of voting rights that may be acquired(if the instrument exercised/converted)

Percentage of voting rights

Total (A+B)

Number of voting rights

Percentage of voting rights

below 3%

below 3%

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

Standard Life Investments Ltd

Proxy Voting:

Name of proxy holder:

Number of voting rights proxy holder will cease to hold:

Date on which proxy holder will cease to hold voting rights:

Additional information:

Contact name:

[email protected] Standard Life Investments Ltd

Contact telephone number:

(0131) 245 6565