The UK’s biggest pension fund on Friday added its voice to criticisms in the City of London of the UK government’s decision to halt the Serious Fraud Office’s inquiry into Saudi arms deals.

Mark Anson, chief executive of Hermes, which manages the BT Pension Scheme, on Friday wrote to Tony Blair, the British prime minister, saying the decision had threatened the UK’s reputation as a leading financial centre and would have a high long-term cost for business and markets.