Containing a plethora of policy measures, Marchs Budget was even more difficult to decipher than normal. But what was clear was the extent to which the Chancellor is willing to tie policy in knots in pursuit of his goal of a Budget surplus by the end of the decade. Mr Osbornes contortions were compelled by a downgrade to tax revenues, reflecting the OBRs gloomier (in our view, too gloomy) view of prospects for productivity. But the implausibly severe fiscal tightening planned for the year before the next general election suggests that another big shift in the trajectory of policy wont be far away.