LONDON (Reuters) - Britain's main political parties are not letting voters know how they would run public finances after the May 7 election, the Institute for Fiscal Studies, an independent think tank, said on Thursday.
The election offers voters the biggest degree of choice over taxation and spending since at least 1992, as Britain's political leaders take different approaches to one of the biggest budget deficits in the rich world.
"All the parties have told us where they are going to increase things, and none of them have given us much detail about where they are going to make people worse off," IFS director Paul Johnson said at a presentation.
The Conservative and Labour parties are neck and neck in opinion polls, with neither likely to win an outright majority.
Prime Minister David Cameron's Conservatives want to eliminate the deficit through deep spending cuts by 2019. Johnson suggested tax rises might also be necessary, given the scale of the party's fiscal ambitions.
The IFS said the Conservatives had only explained where 2 billion of a total 12 billion pounds in welfare spending cuts would come from, a target Johnson said would mean radical change in the social security system.
The main opposition Labour Party has been "considerably more vague" than the Conservatives on how much it would want to borrow, it said.
The think tank estimated Labour's plans would leave Britain with 90 billion pounds more debt than under those of the Conservatives by the end of the decade, the IFS said.
The IFS gave a "small tick" to the Liberal Democrats, the junior partner in the ruling Conservative-led coalition, for the level of fiscal detail in their plans.
But the party sounded too optimistic on the potential savings that could be made by combatting welfare fraud and error and by preventing tax avoidance, the IFS said.
It said the plans of the Scottish National Party, which has an anti-austerity message, actually implied a reduction in departmental spending outside health because the party wants to make welfare more generous.
Reporting by William James; editing by William Schomberg and Andrew Roche