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As filed with the Securities and Exchange Commission on June 4, 2007

Registration No. 333-13276                            

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C.  20549

_______________________

POST-EFFECTIVE AMENDMENT NO. 2 TO THE

FORM F-6
REGISTRATION STATEMENT

under

THE SECURITIES ACT OF 1933

For Depositary Shares Evidenced by American Depositary Receipts


SPIRENT COMMUNICATIONS PLC

(Formerly known as SPIRENT PLC)

 (Exact name of issuer of deposited securities as specified in its charter)

N/A

(Translation of issuer's name into English)

United Kingdom

(Jurisdiction of incorporation or organization of issuer)

THE BANK OF NEW YORK

(Exact name of depositary as specified in its charter)


One Wall Street

 New York, N.Y.  10286

(212) 495-1784

(Address, including zip code, and telephone number, including area code, of depositary's principal executive offices)

__________

The Bank of New York

ADR Division

One Wall Street, 29th Floor

New York, New York, 10286

(212) 495-1784

(Address, including zip code, and telephone number, including area code, of agent for service)


Copies to:

Katherine Ashton, Esq.

Debevoise & Plimpton LLP

Tower 42

Old Broad Street

London EC2N 1HQ

United Kingdom

Peter B. Tisne, Esq.

Emmet, Marvin & Martin, LLP

120 Broadway

New York, New York  10271

(212) 238-3010


It is proposed that this filing become effective under Rule 466

[X] immediately upon filing

[ ] on ( Date ) at ( Time ).

If a separate registration statement has been filed to register the deposited shares, check the following box.  [ ]














The prospectus consists of the proposed form of American Depositary Receipt included as Exhibit A to the form of Deposit Agreement filed as Exhibit 1 to this Registration Statement which is incorporated herein by reference.












PART I


INFORMATION REQUIRED IN PROSPECTUS




Item 1.

Description of Securities to be Registered




Cross Reference Sheet


Location in Form of Receipt

Item Number and Caption

Filed Herewith as Prospectus



1.

Name and address of depositary

Introductory Article


2.

Title of American Depositary Receipts and

Face of Receipt, top center

identity of deposited securities

Terms of Deposit:

(i)

The amount of deposited securities represented

Face of Receipt, upper right corner

by one unit of American Depositary Receipts

(ii)

The procedure for voting, if any,

Articles number 15, 16 and 18

the deposited securities

(iii)

The collection and distribution of

Articles number 4, 12, 13,

dividends

15 and 18

(iv)

The transmission of notices, reports

Articles number 11, 15, 16

and proxy soliciting material

and 18

(v)

The sale or exercise of rights

Articles number 13, 14, 15

and 18


(vi)

The deposit or sale of securities

Articles number 12, 13, 15,

resulting from dividends, splits

17 and 18

or plans of reorganization

(vii)

Amendment, extension or termination

Articles number 20 and 21

of the deposit agreement

(i)

Rights of holders of American Depositary

Article number 11

Receipts to inspect the transfer books of the

depositary and the list of holders of American

Depositary Receipts


(ix)

Restrictions upon the right to deposit

Articles number 2, 3, 4, 5, 6,

or withdraw the underlying securities

8 and 22

(x)

Limitation upon the liability

Articles number 14, 18, 19 and 21

of the depositary



3.

Fees and Charges

Articles number 7 and 8




Item 2.

Available Information


Public reports furnished by issuer

Article number 11












PART II


INFORMATION NOT REQUIRED IN PROSPECTUS




Item 3.

Exhibits


a.

Form of Amended and Restated Deposit Agreement dated as of May 5, 2000, as further amended and restated as of March 23, 2001 and July 10, 2001, among Spirent plc, The Bank of New York as Depositary, and all Owners and Beneficial Owners from time to time of American Depositary Receipts issued thereunder. - Filed herewith as Exhibit 1.

b.

Any other agreement to which the Depositary is a party relating to the issuance of the Depositary Shares registered hereby or the custody of the deposited securities represented.  - Not Applicable.

c.

Every material contract relating to the deposited securities between the Depositary and the issuer of the deposited securities in effect at any time within the last three years. - See (a) above.

d.

Opinion of Emmet, Marvin & Martin, LLP, counsel for the Depositary, as to legality of the securities to be registered. – Filed previously.

e.

Certification under Rule 466.  - Filed herewith as Exhibit 5.



Item 4.

Undertakings

(a)

The Depositary hereby undertakes to make available at the principal office of the Depositary in the United States, for inspection by holders of the ADRs, any reports and communications received from the issuer of the deposited securities which are both (1) received by the Depositary as the holder of the deposited securities, and (2) made generally available to the holders of the underlying securities by the issuer.

(b)

If the amounts of fees charged are not disclosed in the prospectus, the Depositary undertakes to prepare a separate document stating the amount of any fee charged and describing the service for which it is charged and to deliver promptly a copy of such fee schedule without charge to anyone upon request. The Depositary undertakes to notify each registered holder of an ADR thirty days before any change in the fee schedule.



 













SIGNATURES



Pursuant to the requirements of the Securities Act of 1933, the registrant certifies that it has reasonable grounds to believe that all the requirements for filing on Form F-6 are met and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of New York, State of New York, on June 4, 2007.


Legal entity created by the agreement for the issuance of American Depositary Receipts for ordinary shares of Spirent Communications plc.


The Bank of New York,

As Depositary

By: /s/ David S. Stueber

Name:  David S. Stueber

Title:    Managing Director


 












Pursuant to the requirements of the Securities Act of 1933, Spirent Communications plc has caused this Registration Statement to be signed on its behalf by the undersigned thereunto duly authorized, in the City of Crawley, England on June 4, 2007.


SPIRENT COMMUNICATIONS PLC

By: /s/ Eric G. Hutchinson


      Name:  Eric G. Hutchinson

      Title:    Director


    

      


     Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed by the following persons in the capacities indicated on June 4, 2007.


/s/ Edward John Bramson

Director and Acting Chief Executive Officer

Edward John Bramson

(principal executive officer)



/s/ Eric G. Hutchinson

Director and Chief Financial Officer

Eric G. Hutchinson

(principal financial officer and principal accounting officer)


/s/ Ian Brindle

Director

Ian Brindle



/s/ Alexander Walker

Director

Alexander Walker



/s/ Gerard L. Eastman, Jr.

Director

Gerard L. Eastman, Jr.






Spirent Holdings Corporation

Authorized Representative in the United States



By:  /s/ Frank V. Pizzi

  Name:  Frank V. Pizzi

  Title:  President








INDEX TO EXHIBITS


Exhibit

Number

Exhibit

 
   

1

Form of Amended and Restated Deposit Agreement dated as of May 5, 2000, as further amended and restated as of March 23, 2001 and July 10, 2001, among Spirent plc, The Bank of New York as Depositary, and all Owners and Beneficial Owners from time to time of American Depositary Receipts issued thereunder.

 
   

5

Certificate under Rule 466.