Budget polling
The budget is fairly unusual as an event that people actually pay attention to, and which actually has the potential to change voting intention polls. I spend most of my time hear stressing that the ins and outs of Westminster politics, the speeches, the gaffes, the policy launches. Hardly and of it is noticed by normal people who change their vote. Budgets are one of the exceptions - an annual event that does sometimes change minds. Regular readers will recognise the chart below from its outings at previous budgets - it shows the two YouGov polls before and after each recent budget (in recent years, its the weekly averages for the two weeks before and after each budget).
Effect of past budgets on government lead in YouGov polling
As you can see, while there is often talk of Chancellors revealing great vote winning bribes in budgets, when they do have an effect it is more often a negative one. Budgets can have a positive effect (2003, 2006 and 2011 all look like they shifted things marginally in the government's favour), generally speaking the only big budget effects are negative ones - in 2008 and 2009 Alistair Darling had to deliver news of just how bad the economy was, while the 2012 budget contained the pasty tax, the granny tax and the 45p tax rate.
Anyway, while we'll have the usual YouGov voting intention overnight, remember that the overwhelming majority of that will have been conducted before the budget was given. The actual figures we need to look out for will be those published Thurs/Fri night, and those published in the Sunday papers once the ups and downs of the budget have had time to register with the public.