A furious row over who was to blame for the Budget “shambles” erupted last night after it emerged that the Cabinet was never briefed that the Tory manifesto was being breached.

Philip Hammond’s hour-long briefing to Cabinet colleagues failed to mention that a tax rise on the self-employed clashed with a Tory election promise, it can be revealed.

Cabinet sources have blamed the subsequent damaging headlines on the Treasury’s failure to detect the political danger and warn ministers. However, Treasury figures have pointed the finger at No 10 and its demand for spending to protect Theresa May’s “just about managing” families.