UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 6-K REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16 UNDER THE SECURITIES EXCHANGE ACT OF 1934 For the month of May, 2004 SPIRENT plc _____________________________________________________________________ (Translation of registrant's name into English) Spirent House, Crawley Business Quarter, Fleming Way, Crawley, West Sussex RH10 9QL, UK. _____________________________________________________________________ (Address of principal executive offices) Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F. Form 20-F X Form 40-F..... Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934. Yes ..... No X If "Yes" is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): 82- ________ SCHEDULE 11 NOTIFICATION OF INTERESTS OF DIRECTORS AND CONNECTED PERSONS 1. Name of company SPIRENT PLC 2. Name of director FREDERICK D'ALESSIO 3. Please state whether notification indicates that it is in respect of holding of the shareholder named in 2 above or in respect of a non-beneficial interest or in the case of an individual holder if it is a holding of that person's spouse or children under the age of 18 or in respect of a non-beneficial interest IN RESPECT OF THE DIRECTOR'S HOLDING 4. Name of the registered holder(s) and, if more than one holder, the number of shares held by each of them (if notified) NOT NOTIFIED 5. Please state whether notification relates to a person(s) connected with the director named in 2 above and identify the connected person(s) N/A 6. Please state the nature of the transaction. For PEP transactions please indicate whether general/single co PEP and if discretionary/non discretionary ACQUISITION OF SHARES 7. Number of shares / amount of stock acquired 7,000 8. Percentage of issued class 0.003% 9. Number of shares/amount of stock disposed N/A 10. Percentage of issued class N/A 11. Class of security SPIRENT AMERICAN DEPOSITARY RECEIPTS (ADRs). SEE ADDITIONAL INFORMATION 12. Price per share 2,300 ADRs AT $4.08 PER ADR 4,700 ADRs AT $4.10 PER ADR 13. Date of transaction 17 MAY 2004 14. Date company informed 17 MAY 2004 15. Total holding following this notification 7,000 ADRs 16. Total percentage holding of issued class following this notification 0.003% If a director has been granted options by the company please complete the following boxes. 17. Date of grant N/A 18. Period during which or date on which exercisable N/A 19. Total amount paid (if any) for grant of the option N/A 20. Description of shares or debentures involved: class, number N/A 21. Exercise price (if fixed at time of grant) or indication that price is to be fixed at time of exercise N/A 22. Total number of shares or debentures over which options held following this notification N/A 23. Any additional information THE COMPANY HAS ORDINARY SHARES EACH OF 3.3333 PENCE NOMINAL VALUE. THE ORDINARY SHARES ARE ALSO TRADED ON THE NEW YORK STOCK EXCHANGE IN THE FORM OF AMERICAN DEPOSITARY SHARES AND THESE ARE EVIDENCED BY AMERICAN DEPOSITARY RECEIPTS, EACH ONE OF WHICH REPRESENTS FOUR ORDINARY SHARES. THE ABOVE SHARES WERE PURCHASED IN THE FORM OF AMERICAN DEPOSITARY RECEIPTS. 24. Name of contact and telephone number for queries LUKE THOMAS - 01293 767658 25. Name and signature of authorised company official responsible for making this notification LUKE THOMAS - DEPUTY COMPANY SECRETARY Date of Notification 18 MAY 2004 The FSA does not give any express or implied warranty as to the accuracy of this document or material and does not accept any liability for error or omission. The FSA is not liable for any damages (including, without limitation, damages for loss of business or loss of profits) arising in contract, tort or otherwise from the use of or inability to use this document, or any material contained in it, or from any action or decision taken as a result of using this document or any such material. Signatures Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. ______LUKE THOMAS______ (Registrant) Date 18 May 2004 By ____/s/ Luke Thomas____ (Signature)*