The most important number is £12.5 trillion

Many numbers are being thrown around in the wake of the budget most notably 50 per cent and £175b but this excellent post from Chris Dillon maybe puts something into perspective.

The most important number about today’s Budget is $12.5 trillion. That’s the amount of money the private sector is likely to save around the world this year*.
This means that the government can raise the £220bn it plans to borrow in the gilt market merely by attracting 2.5 pence for every pound saved**. This is smaller than the share of the UK in the global economy.