1.

Identity of the issuer or the underlying issuer of existing shares to which voting rights are attached

CELOXICA HOLDINGS PLC

2.

Reason for the notification (please tick the appropriate box or boxes)

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

(  )

Other (specify):

Initial disclosure under DTR 5

(X)

3.

Full name of person(s) subject to the notification obligation:

Advent Venture Partners LLP    

4.

Full name of shareholder(s) (if different from 3.) (NB abbreviation noted in brackets)

Advent Private Equity Fund III 'A' (APEF3A);
Advent Private Equity Fund III 'B' (APEF3B);
Advent Private Equity Fund III 'C' (APEF3C);
Advent Private Equity Fund III 'D' (APEF3D);
Advent Private Equity Fund III GmbH & Co KG (APEF3KG);
Advent Private Equity Fund III Affiliates (APEF3Aff);
Advent Management III Limited Partnership (AM3LP)

5.

Date of the transaction (and date on which the threshold is crossed or reached if different):

6.

Date on which issuer notified:

19 March 2007

7.

Threshold(s) that is/are crossed or reached:

28%

8.

Notified details:

Class/type of shares (if possible using the ISIN code)

Ordinary (GB00B0L9TZ33)

Situation previous to the triggering transaction

Resulting situation after the triggering transaction

Number of Shares

Number of Voting Rights

Number of shares

Number of voting rights

% of voting rights

Direct

Direct

Indirect

Direct

Indirect

19,682,921*
*: comprised of

APEF3A: 9,960,270

APEF3B: 4,880,597

APEF3C: 1,361,426

APEF3D: 2,677,905

APEF3KG: 385,308

APEF3Aff: 321,091

AM3LP: 96,324

28.020%*
*: comprised of:

APEF3A: 14.179%

APEF3B: 6.948%

APEF3C: 1.938%

APEF3D: 3.812%

APEF3KG: 0.549%

APEF3Aff: 0.457%

AM3LP: 0.137%

Expiration date

Exercise/Conversion Period/Date

Number of voting rights that may be acquired if the instrument is exercised/converted

% of voting rights

Refer A above

Number of voting rights

% of voting rights

Refer A above

9.

Chain of controlled undertakings through which the voting rights and/or the financial instruments are effectively held, if applicable:

Advent Venture Partners LLP owns 100% of Advent Limited. Advent Limited owns 100% of Advent Private Equity GmbH, which is the general partner of Advent Private Equity Fund III GMBH & CO KG. Advent Limited also owns 100% of Advent Management III Limited, which is the general partner of Advent Management III Limited Partnership, which is general partner of each of Advent Private Equity Fund III ‘A’ Limited Partnership, Advent Private Equity Fund III ‘B’ Limited Partnership, Advent Private Equity Fund III ‘C’ Limited Partnership, Advent Private Equity Fund III ‘D’ Limited Partnership and Advent Private Equity Fund III Affiliates Limited Partnership.

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: