Conservative Party leader David Cameron sought this afternoon to convince voters that his plan to partly reverse a planned payroll tax rise did add up after an adviser gave new details of how the policy might be paid for.
Bidding to lead his party back into power in a May 6th election shaping up to be tight, Cameron needs to overcome a perception among some voters, fuelled by attacks from the ruling Labour Party, that his economic plans are unrealistic.
The Conservatives are ahead in the polls but not by a big enough margin to be sure of winning an overall majority in parliament. If they fall short of that goal, a variety of outcomes are possible including another Labour government.
"All these claims that Labour have been making that it is not deliverable to save £12 billion (sterling) gross, £6 billion pounds net in the first year of Conservative government simply are not right," Mr Cameron said on BBC radio.
"It is doable. It is deliverable," he said.
He was referring to a pledge to use "efficiency savings" in the public sector to pay for exempting seven out of 10 workers from the planned rise in National Insurance payroll tax. British prime minister Gordon Brown says Mr Cameron's figures "do not add up".
A former government adviser now working for Cameron, Peter Gershon, told the Financial Times the savings could come from not filling public sector vacancies, cutting spending on IT, consultants and staff expenses, and renegotiating contracts.
These were the most detailed comments so far on where the promised savings would come from, although Mr Cameron stopped short of confirming them, saying the exact balance would be decided "calmly and reasonably" by his newly elected government.
Since the Conservative finance spokesman, George Osborne, announced the policy on Monday, it has completely dominated the first week of formal election campaigning, with Labour on the back foot as dozens of business leaders backed the proposal.
Labour's Alistair Darling, the finance minister, appeared to concede on Friday the Conservatives had scored a point.
"(It is) another example where they may have got the political tactics right for the first day or so but their overall judgment is just plain wrong," he said.
Mr Darling stuck to Labour's line of attack that there are no easy efficiency savings to be made, and therefore the Conservatives would have to take an axe to public spending, threatening a fragile recovery from a deep recession.
This is a central campaign issue. Everyone agrees on the need to tackle a £167-billion budget deficit weighing on investor confidence and threatening Britain's triple-A credit rating, but the parties disagree on how and when to do it.
Andrew Hawkins of the ComRes polling company said the National Insurance row had gone well for the Conservatives.
"To land a blow on the economy is a considerable achievement for the Conservatives given that they've made so little progress on that over the past couple of years," he said.
Mr Cameron also said today that if elected he would reduce public sector pay disparities, seeking to show that under his leadership the Conservatives did not represent the interests of the wealthy but rather cared about inequality.
"There's a real problem here which is the public sector and the private sector sort of chase each other's tail in endlessly increasing top people's pay," he said, describing current pay inequalities as "outrageous".
"We're saying this roundabout needs to stop and let's start with the public sector and say...bosses shouldn't be paid more than 20 times more than the people who are paid the least."
Reuters