Dialight Regulatory News (DIA)

For filings with the FSA include the annex

For filings with issuer exclude the annex

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARES

1. Identity of the issuer or the underlying issuerof existing shares to which voting rights areattached: ii

Dialight 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 qualifying financial instruments which may result in the acquisition of shares already issued to which voting rights are attached

An acquisition or disposal of instruments with similar economic effect to qualifying financial instruments

An event changing the breakdown of voting rights

Other (please specify):

3. Full name of person(s) subject to thenotification obligation: iii

BlackRock, Inc.

4. Full name of shareholder(s)  (if different from 3.):iv

5. Date of the transaction and date onwhich the threshold is crossed orreached: v

2nd May 2012

6. Date on which issuer notified:

4th May 2012

7. Threshold(s) that is/are crossed orreached: vi, vii

Holding has gone below 16%

8. Notified details:

A: Voting rights attached to shares viii, ix

Class/type ofshares

if possible usingthe ISIN CODE

Situation previousto the triggeringtransaction

Resulting situation after the triggering transaction

NumberofShares

NumberofVotingRights

Numberof shares

Number of votingrights

% of voting rights x

Direct

Direct xi

Indirect xii

Direct

Indirect

GB0033057794

5,014,576

5,014,576

N/A

N/A

5,019,406

N/A

15.61%

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financialinstrument

Expirationdate xiii

Exercise/Conversion Period xiv

Number of votingrights that may beacquired if theinstrument isexercised/ converted.

% of votingrights

C: Financial Instruments with similar economic effect to Qualifying Financial Instruments xv, xvi

Resulting situation after the triggering transaction

Type of financialinstrument

Exercise price

Expiration date xvii

Exercise/Conversion period xviii

Number of voting rights instrument refers to

% of voting rights xix, xx

CFD

100,000

Nominal

Delta

0.31%

0.31%

Total (A+B+C)

Number of voting rights

Percentage of voting rights

5,119,406

15.92%

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

BlackRock Investment Management (UK) Limited - 5,119,406 (15.92%)

Proxy Voting:

10. Name of the proxy holder:

11. Number of voting rights proxy holder will ceaseto hold:

12. Date on which proxy holder will cease to holdvoting rights:

13. Additional information:

BlackRock International Threshold Reporting Team

14. Contact name:

Blackrock - Andrew Manchester

Dialight - Nick Giles

15. Contact telephone number:

Blackrock - 020 7743 5773

Dialight - 01638 778641