A bust of the former prime minister once voted the greatest Briton in history, which was loaned to George W Bush from the Government's art collection after the September 11 attacks, has now been formally handed back.

The bronze by Sir Jacob Epstein, worth hundreds of thousands of pounds if it were ever sold on the open market, enjoyed pride of place in the Oval Office during President Bush's tenure.

But when British officials offered to let Mr Obama to hang onto the bust for a further four years, the White House said: "Thanks, but no thanks."