Welfare and Pensions Secretary Iain Duncan Smith's flagship benefit reform was savaged yesterday by senior MPs highlighting "shocking failures" that have already wasted at least £140 million.

The cross-party Commons public accounts committee (PAC) said the botched universal credit plans suffer from "alarmingly weak" management which has seen secretarial staff put in charge of purchase orders worth over £20m.

MPs said personal assistants had approved single payments of £8.7m, 22.6m and 1.1m - despite not have the authority to do so.