Leading analysts warned of a difficult year for investment banks amid fears that the debt capital markets remain weak.

The council went to the debt capital markets after pulling out of earlier negotiations with banks.

If the superinvestor took the long-term risk, providing equity for these projects, it would unlock billions of pounds in debt capital from the private sector.

He said the transaction had been straightforward and the move was an opportunist one to lock in some funding at a time when debt capital markets were at their hottest.

Fees from debt capital markets underwriting increased by 26 per cent compared with the previous year and accounted for 30 per cent of overall investment bank fees.