The Liberal Democrats promised to go "further and faster" on raising personal tax allowances, after Chancellor George Osborne refused to rule out cutting the top rate of income tax to 40p in the next parliament.
The Lib Dems - who claim they had to push the Conservatives into accepting rises in allowances at a succession of coalition budgets and accused their former coalition partners of "unbelievable cheek" for trying to take credit for the policy - are expected to unveil more radical proposals this week.
Education Minister David Laws said the proposals will be high on the agenda "before even the first cup of coffee has been served" should the Lib Dems be part of coalition talks after May 7th.
"The Liberal Democrats... would want to go far faster than the existing trajectory for increasing the personal tax allowance," he told BBC Radio 5 Live.
The personal tax allowance would rise to £12,500 under the Lib Dems, funded by a crackdown on tax dodgers, leader Nick Clegg has revealed.
Millions of households would be better off under a Tory government, David Cameron will claim today as he hails "money-back Monday".
A Conservative government would aim to double the number of first-time buyers by 2020, the Chancellor has declared.