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 January, 2003 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- ________ BLOCK LISTING SIX MONTHLY RETURN To: Listing Applications UK Listing Authority Old Broad Street London EC2N 1HP (020 7588 6057) Name of company: SPIRENT PLC Name of scheme: CAW AMENDED AND RESTATED STOCK OPTION PLAN Period of return: From: 01 JULY 2002 To: 31 DECEMBER 2002 Number and class of share(s) 0 ORDINARY SHARES OF 3 1/3p EACH (amount of Stock/debt security) not issued under scheme at end of the last period: Number of shares issued/allotted 23,744 ORDINARY SHARES under scheme during period: Balance under scheme not yet 1,391,650 ORDINARY SHARES issued/allotted at end of period: Number and class of share(s) 1,300,000 ORDINARY SHARES OF 3 1/3p EACH (amount of stock/debt DATED 15 AUGUST 2002 securities) originally listed and the date of admission: 115,394 ORDINARY SHARES OF 3 1/3P EACH DATED 28 AUGUST 2002 Please confirm total number of shares in issue at the end of the period in order for us to update our records 939,438,028 Contact for queries: Address: Spirent plc Name: Michael Anscombe Spirent House Telephone: 01293 767676 Crawley Business Quarter Fleming Way Crawley, RH10 9QL Person making return Name: Michael Anscombe Position: Assistant Company Secretary Signature: BLOCK LISTING SIX MONTHLY RETURN To: Listing Applications UK Listing Authority Old Broad Street London EC2N 1HP (020 7588 6057) ALL FIGURES HAVE BEEN REVISED FOR THE 3:1 SHARE SPLIT ON 11 MAY 2000 Name of company: SPIRENT PLC Name of scheme: SPIRENT EXECUTIVE SHARE OPTION SCHEME Period of return: From: 01 JULY 2002 To: 31 DECEMBER 2002 Number and class of share(s) 1,587,494 ORDINARY SHARES OF 3 1/3p EACH (amount of Stock/debt security) not issued under scheme at end of the last period: Number of shares issued/allotted 0 ORDINARY SHARES under scheme during period: Balance under scheme not yet 1,587,494 ORDINARY SHARES issued/allotted at end of period: Number and class of share(s) 3,000,000 ORDINARY SHARES OF 3 1/3p (amount of stock/debt EACH DATED 29/09/2000 securities) originally listed and the date of admission: Please confirm total number of shares in issue at the end of the period in order for us to update our records 939,438,028 Contact for queries: Address: Spirent plc Name: Michael Anscombe Spirent House Telephone: 01293 767676 Crawley Business Quarter Fleming Way Crawley, RH10 9QL Person making return Name: Michael Anscombe Position: Assistant Company Secretary Signature: BLOCK LISTING SIX MONTHLY RETURN To: Listing Applications UK Listing Authority Old Broad Street London EC2N 1HP (020 7588 6057) Name of company: SPIRENT PLC Name of scheme: U.S. EMPLOYEE STOCK PURCHASE PLAN Period of return: From: 01 JULY 2002 To: 31 DECEMBER 2002 Number and class of share(s) 994,000 ORDINARY SHARES OF 3 1/3p EACH (amount of Stock/debt security) not issued under scheme at end of the last period: Number of shares issued/allotted 33,322 ORDINARY SHARES under scheme during period: Balance under scheme not yet 7,960,678 ORDINARY SHARES issued/allotted at end of period Number and class of share(s) 435,000 ORDINARY SHARES OF 3 1/3P EACH (amount of stock/debt ADMITTED 5 JUNE 2001 securities) originally listed and the date of admission: 3,500,000 ORDINARY SHARES OF 3 1/3p EACH ADMITTED 1 NOVEMBER 2001 7,000,000 ORDINARY SHARES OF 3 1/3P EACH ADMITTED 18 NOVEMBER 2002 Please confirm total number of shares in issue at the end of the period in order for us to update our records 939,438,028 Contact for queries: Address: Spirent plc Name: Michael Anscombe Spirent House Telephone: 01293 767676 Crawley Business Quarter RH10 9QL Person making return Name: Michael Anscombe Position: Assistant Company Secretary Signature: BLOCK LISTING SIX MONTHLY RETURN To: Listing Applications UK Listing Authority Old Broad Street London EC2N 1HP (020 7588 6057) Name of company: SPIRENT PLC Name of scheme: GLOBAL ALL EMPLOYEE SHARE PURCHASE PLAN Period of return: From: 01 JULY 2002 To: 31 DECEMBER 2002 Number and class of share(s) 0 ORDINARY SHARES OF 3 1/3p EACH (amount of Stock/debt security) not issued under scheme at end of the last period: Number of shares issued/allotted 0 ORDINARY SHARES under scheme during period: Balance under scheme not yet 1,000,000 ORDINARY SHARES issued/allotted at end of period Number and class of share(s) 1,000,000 ORDINARY SHARES OF 3 1/3p EACH (amount of stock/debt DATED 18 NOVEMBER 2002 securities) originally listed and the date of admission: Please confirm total number of shares in issue at the end of the period in order for us to update our records 939,438,028 Contact for queries: Address: Spirent plc Name: Michael Anscombe Spirent House Telephone: 01293 767676 Crawley Business Quarter RH10 9QL Person making return Name: Michael Anscombe Position: Assistant Company Secretary Signature: BLOCK LISTING SIX MONTHLY RETURN To: Listing Applications UK Listing Authority Old Broad Street London EC2N 1HP (020 7588 6057) ALL FIGURES HAVE BEEN REVISED FOR THE 3:1 SHARE SPLIT ON 11 MAY 2000 Name of company: SPIRENT PLC Name of scheme: NETCOM AMENDED AND RESTATED STOCK OPTION PLAN Period of return: From: 01 JULY 2002 To: 31 DECEMBER 2002 Number and class of share(s) 1,593,040 ORDINARY SHARES OF 3 1/3p EACH (amount of Stock/debt security) not issued under scheme at end of the last period: Number of shares issued/allotted 1,390,271 ORDINARY SHARES under scheme during period: Balance under scheme not yet 6,925,458 ORDINARY SHARES issued/allotted at end of period: Number and class of share(s) 3,291,399 ORDINARY SHARES OF 3 1/3p EACH (amount of stock/debt DATED 03/09/1999 securities) originally listed and the date of admission: 1,739,130 ORDINARY SHARES OF 3 1/3p EACH DATED 8 JULY 2002 6,722,689 ORDINARY SHARES OF 3 1/3P EACH DATED 8 OCTOBER 2002 Please confirm total number of shares in issue at the end of the period in order for us to update our records 939,438,028 Contact for queries: Address: Spirent plc Name: Michael Anscombe Spirent House Telephone: 01293 767676 Crawley Business Quarter Fleming Way Crawley, RH10 9QL Person making return Name: Michael Anscombe Position: Assistant Company Secretary Signature: BLOCK LISTING SIX MONTHLY RETURN To: Listing Applications UK Listing Authority Old Broad Street London EC2N 1HP (020 7588 6057) Name of company: SPIRENT PLC Name of scheme: ZARAK AMENDED AND RESTATED STOCK OPTION PLAN Period of return: From: 01 JULY 2002 To: 31 DECEMBER 2002 Number and class of share(s) 2,750,976 ORDINARY SHARES OF 3 1/3p EACH (amount of Stock/debt security) not issued under scheme at end of the last period: Number of shares issued/allotted 59,980 ORDINARY SHARES under scheme during period: Balance under scheme not yet 2,690,996 ORDINARY SHARES issued/allotted at end of period: Number and class of share(s) 3,895,474 ORDINARY SHARES OF 3 1/3p EACH (amount of stock/debt DATED 14 NOVEMBER 2000 securities) originally listed and the date of admission: Please confirm total number of shares in issue at the end of the period in order for us to update our records 939,438,028 Contact for queries: Address: Spirent plc Name: Michael Anscombe Spirent House Telephone: 01293 767676 Crawley Business Quarter Fleming Way Crawley, RH10 9QL Person making return Name: Michael Anscombe Position: Assistant Company Secretary Signature: 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___January 6, 2003____ By ____/s/ Luke Thomas____ (Signature)*