With his reputation as a political fixer, he became known as the Prince of Darkness. But when Peter Mandelson was caught taking a leak in public it was an episode even he couldn’t spin his way out of. The former US ambassador was left red-faced after being spotted relieving himself against a wall following a visit to George Osborne ’s Notting Hill pad. Lord Mandelson, 72, was snapped on Wednesday evening after the trip to the former Tory Chancellor’s multi-million pound townhouse in London. He