Two of the UK’s clearing banks were raided by the Office of Fair Trading regarding possible price fixing on loans to professional services firms.

The watchdog confirmed it had visited the offices of Barclays and the Royal Bank of Scotland as part of its investigation.

‘The OFT will not be in a position to conclude whether the law has in fact been infringed until it has completed its investigation and assessed the available evidence,' it said in a statement.

The investigation was triggered after Barclays contacted the OFT in March about its professional service team being ‘approached from outside in an ‘inappropriate manner’.

A Royal Bank of Scotland spokesperson said: ‘We are, as always, co-operating fully with the Regulatory authorities and it would therefore be inappropriate to comment further.’