Osborne's weakness suddenly becomes a big headache for Cameron

The chancellor's budget disaster comes at a time when the prime minister needs him to play a pivotal role in the EU debate

Britain faces a cocktail of economic risks. Such has been George Osborne's persistent message since the start of 2016. He talked about the slowdown in China. He fretted about the turmoil in financial markets. He warned that growth was still weak in the eurozone. What probably never crossed the chancellor's mind was that speculation over his own future might be part of the mix.

There is no getting away from the fact that the budget and its aftermath have been a political and personal disaster for Osborne. Even while he was speaking, it was clear that the package would quickly fall to pieces. The budget could only make the sums add up through blatant accounting tricks. It announced tax cuts at the same time as it cut estimates for Britain's long-term growth potential. Even worse, it provided tax breaks for the better off at the same time as it targeted the disabled.

Related: If I were George Osborne I'd be starting to sweat about Tory unpopularity | Martin Kettle