When it comes to pensions, Gordon Brown will need to tread carefully following the uproar surrounding the 75p pension increase announced earlier in the year and he may want to consider older voters may well cast the deciding votes in the next general election.

Mr Brown has been sticking to his guns on his refusal to raise the basic pension, and has promised only that "in the pre-Budget report we will do best by Britain's pensioners".

The chancellor's offering will likely include an increase in means-tested payments aimed at supplementing the income of the poorest pensioners.

However, Labour party members and backbenchers, as well as pressure groups, have been seeking to increase the basic pension to as much as £90 a week. Labour MPs are probably looking for the government to undo the damage inflicted by the 75p increase in time for the next election to help avoid a repeat of the loss of party council seats suffered in May's local elections.

Gordon Lishman, the director-general of Age Concern, who has warned research shows that older people are more likely to get out and vote at the next election, said he was looking for Mr Brown to announce a significant step towards the £90 basic pension figure.

While Mr Lishman supports government plans to increase means-tested benefits, he says this is insufficient because a large number of those eligible for the benefits fail to claim because of a lack of information or fear of stigma. He said he also wanted an assurance that the government would commission research into pensioner living costs.

At the party's conference in September Tony Blair suffered his first defeat at a party conference when a vote on a motion calling for an "immediate and substantial increase in the basic pension" was supported by more than 60 per cent of delegates. Mr Brown said at the time he would not bow to union pressure on pensions.

However, choosing not to increase the basic pension would also mean ignoring the advice of the Labour-dominated parliamentary social security committee of MPs. In August, the committee urged the government to increase the non-means tested pension to £90. The committee said the minimum income guarantee was not working because of the low take-up rate.

"We have concluded that an increase in the state non-means-tested pension is inevitable and that it should be done sooner rather than later," the MPs said in their report on pensioner poverty.

If, on Wednesday, Mr Brown announces an inflation only rise in the basic state pension, the weekly allowance would go up to about £70. If he raises the minimum income guarantee in line with earnings only, it would rise to about £82.