Holding(s) in Company

Porvair PLC
11 May 2006

Letter to: RNS

SECTION 198 COMPANIES ACT 1985 - 3% NOTIFIABLE INTEREST

We have been advised of the following holding by Schroder Investment Management
Limited held in portfolios managed by them on a discretionary basis.

Registered owner                          No. of shares             % holding

Schroder Unit Trusts Ltd (SUTL)               5,986,294            
 
British Coal Staff Superannuation a/c:P       1,083,322               
Chase Nominees Limited                          389,188
Mineworkers' Pension Scheme a/c:R             1,388,906
Nortrust Nominees Limited                       491,561

                                              9,339,271                 23.02  

Letter from: Chris Tyler
             Company Secretary
             Porvair plc


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