Notification of Major Interest in Shares

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARESⁱ

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

Porvair 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):

Change of Custodian

X

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

Prudential plc group of companies

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

See attached schedule

5. Date of the transaction and date on
which the threshold is crossed or
reached: ^v

03 October 2011

6. Date on which issuer notified:

04 October 2011

7. Threshold(s) that is/are crossed or
reached: ^{vi, vii}

See item 13

8. Notified details:

A: Voting rights attached to shares ^{viii, ix}

Class/type of
shares

if possible using
the ISIN CODE

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 ^x

Direct

Direct ^xi

Indirect ^xii

Direct

Indirect

GB0006963689

6,080,987

6,080,987

6,080,987

6,080,987

0

14.33

0

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financial
instrument

Expiration
date ^xiii

Exercise/
Conversion Period ^xiv

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

% of voting
rights

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

Resulting situation after the triggering transaction

Type of financial
instrument

Exercise price

Expiration date ^xvii

Exercise/
Conversion period ^xviii

Number of voting rights instrument refers to

% of voting rights ^{xix, xx}

Nominal

Delta

Total (A+B+C)

Number of voting rights

Percentage of voting rights

6,080,987

14.33

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

Prudential plc (parent Company)

M&G Group Limited (wholly owned subsidiary of Prudential plc)

M&G Limited (wholly owned subsidiary of M&G Group Limited)

M&G Investment Management Limited (wholly owned subsidiary of M&G Limited)

M&G Securities Limited (wholly owned subsidiary of M&G Limited)

Proxy Voting:

10. Name of the proxy holder:

N/A

11. Number of voting rights proxy holder will cease
to hold:

N/A

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

N/A

13. Additional information:

Following a change of custodian for a large number of funds managed by M&G, the registration details have changed and are now as detailed on the attached report. No other material changes have taken place.

14. Contact name:

James Todd / Mark Thomas

M&G Investment Management Limited

15. Contact telephone number:

020 7548 2293 / 020 7548 3266