Gordon Brown is expected to open the coffers

He told BBC One's Breakfast With Frost programme on Sunday: "We don't just believe that having raised people's taxes as they have, we should blow all the money in three years.

"You see, they want to win the election, they want to spend their way to winning the election, by bribing the electorate with their own money. They have no care for tomorrow."

In recent weeks the government appears to have been on the back foot with opinion polls suggesting a fall in Labour support across the country compared to the high levels of the government's early years.

Tory leader William Hague admitted on Tuesday that a future Conservative government would not cut taxes as a share of the nation's income if the economy hit hard times.

'�11,500 spent every second'

The modification of the Tory "tax guarantee" came - it is believed - after weeks of pressure from Mr Portillo.

Outlining how he would spend public money, should the Conservatives win the next election, Mr Portillo told the programme: "We are going to do something that is sustainable."

We focused on getting the economy into shape

Mo Mowlam

He said a Conservative government would provide better public services than Labour, but refused to say it would spend less money.

He said: "If you plan on a sustainable policy of public spending, then year after year you can do that, the thing won't go wrong, the thing won't come apart in your hands, you will be able to spend more.

"But in the intervening years when we're keeping control of public spending, making sure it grows just as fast as the economy - in those years we are putting pressure on civil servants, on people who administer our budgets to do things more efficiently, to achieve value for money, to get rid of bureaucracy, to get rid of red tape."

He said �11,500 of public money was spent every second, and that there was no way the sum could not be spent more efficiently.

Mowlam hits back

But Mr Portillo came under fire from Cabinet Office minister Mo Mowlam who said the MP could not pledge to spend less on public spending than would be received in terms of economic growth, without saying where cuts would be made.

She told the programme: "We have money that due to economic prudence we have got to spend.

"We said that we would stick within the previous government's spending reviews when we came into government and we did. Now we have money, not that we are going to 'splurge' as Michael Portillo kept saying.

"We are very clear on the strategies that we want to follow: We want to put more into health, some into education, some into crime and that will be announced this week, and that is sustainable because we focused on getting the economy into shape."

Dr Mowlam added: "We have made clear what we have got and we are going to spend it, but then of course we're going to look at the situation, we're not naively saying this is going to carry on ad infinitum."

The Comprehensive Spending Review is an innovation of the chancellor, who delivered the first in 1998.