Payments under the Single Payment Scheme and other EU direct aid schemes (Area Payment for Nuts, Aid for Energy Crops and Protein Crop Premium) are set in Euros and are converted to sterling each year using exchange rates calculated in accordance with EU Regulations.
 
That rate is the last one set by the European Central Bank (ECB) in September, this has been confirmed as €1 = £0.79030
 
Notes:
The exchange rate set for 2007 payments was €1 = £ 0. 69680