Ever since the credit crisis started, Barclays has been the subject of intense speculation from investors trying to gauge the British bank’s exposure to the turmoil. In recent months, its method of accounting for some debt instruments on its balance sheet has become the main topic of debate between the bank and its critics.

The debate flared up again last week when, in the wake of Barclays’ £4.5bn share issue, analysts at Citigroup pointed to what they describe as the bank’s “unusual” accounting practices.