Great Portland Estates PLC 10 April 2007 TR-1: NOTIFICATION OF MAJOR INTERESTS IN SHARES (1). Identity of the issuer or the underlying issuer of existing shares to which voting rights are attached: Great Portland Estates 2. Reason for the notification (please state Yes/No): ( ) An acquisition or disposal of voting rights: ( ) An acquisition or disposal of financial instruments which may result in the acquisition of shares already issued to which voting rights are attached: ( ) An event changing the breakdown of voting rights: ( X ) Other (please specify) : ( ) 3. Full name of person(s) subject to the notification obligation: Henderson Global Investors Ltd 4. Full name of shareholder(s) (if different from 3.): 5. Date of the transaction and date on which the threshold is crossed or reached if different): 6. Date on which issuer notified: 2nd April 7. Threshold(s) that is/are crossed or reached: 7% 8. Notified details: A: Voting rights attached to shares Class/type of shares Situation previous to if possible using the the Triggering ISIN CODE transaction Number of shares Number of voting Rights Great 12,391,561 12,391,561 Portland Estates GBP 0.125 Resulting situation after the triggering transaction Class/type of shares Number of shares Number of voting rights % of voting rights if possible using the ISIN CODE Direct Direct Indirect Direct Indirect 12,391,561 12,391,561 6.84% B: Financial Instruments Resulting situation after the triggering transaction Type of Expiration Date Exercise/Conversion Number of voting % of voting financial Period/ Date rights that may be rights instrument acquired if the instrument is exercised/ converted. Total (A+B) Number of voting rights % of voting rights 12,391,561 6.84% 9. Chain of controlled undertakings through which the voting rights and/or the financial instruments are effectively held, if applicable: Proxy Voting: 10. Name of the proxy holder: 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: 15. Contact telephone number: Annex Notification Of Major Interests In Shares A: Identity of the person or legal entity subject to the notification obligation Full name (including legal form for legal entities): Contact address (registered office for legal entities): Phone number: Other useful information (at least legal representative for legal persons): B: Identity of the notifier, if applicable Full name: Contact address: Phone number: Other useful information (e.g. functional relationship with the person or legal entity subject to the notification obligation): C: Additional information : This information is provided by RNS The company news service from the London Stock Exchange