Notifiable Interest

Tristel PLC 06 July 2007 Tristel PLC ('the Company') Notifiable Interest A form TR-1 containing the following information has been received by the Company. 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: Tristel PLC 2. Reason for the notification DTR disclosure requirements 3. Full name of person(s) subject to the notification obligation: Peter Stephens 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): n/a 6. Date on which issuer notified: 06/07/07 7. Threshold(s) that is/are crossed or reached: > 3% 8. Notified details: A: Voting rights attached to shares Class/type of Situation previous to Resulting situation after the triggering transaction shares Triggering transaction Notification required under DTR transitional provision 7 if possible using ISIN CODE Number of Number of Number of Number of voting % of voting rights Shares Voting Rights shares rights Direct Direct Indirect Direct Indirect 786,954 786,954 3.22% B: Financial Instruments Resulting situation after the triggering transaction Type of financial Expiration date Exercise/ Number of voting % of voting rights instrument Conversion Period/ rights that may be Date acquired if the instrument is exercised/ converted Total (A+B) Number of voting rights % of voting rights 786,954 3.22% 9. Chain of controlled undertakings through which the voting rights and/or the financial instruments are effectively held, if applicable: N/A 10. Name of the Proxy holder: n/a 11. Number of voting rights proxy holder will cease to hold: n/a 12. Date on which proxy holder will cease to hold voting rights: n/a 13. Additional information: 20,000 shares acquired at a price of 60.5 pence each 14. Contact name: Contact Peter Stephens 15. Contact telephone number: 0207 4932662 This information is provided by RNS The company news service from the London Stock Exchange