Net Asset Value(s)

British Portfolio Trust PLC
14 September 2007


British Portfolio Trust PLC

As recommended by the AIC, financial assets are now valued on a bid price basis
in accordance with revised UK accounting standards.

British Portfolio Trust PLC announces that at close of business on 13 September
2007:
     
1)   Excluding any profit or loss on the mark to market value of the company's 
     fixed interest swap contract, the capital net asset value per ordinary
     share was 188.12p.
     
2)   based on the number of shares held in treasury, the net asset value per
     ordinary share was 187.88p.

The NAV at market value will no longer be announced as the fair value of the
interest rate swap contracts is now recognised in the financial statements in
accordance with the adoption of FRS26 'Financial Investments: Measurement'.


Enquiries:
Peter Ingram
Tel: [phone]
14 September 2007


                      This information is provided by RNS
            The company news service from the London Stock Exchange