NOTHING so focuses the mind of a politician as the threat of losing office. John Redwood understands that very well. When Conservative MPs vote on Tuesday, he said, they will be asking themselves: "Who gives me the best chance of me keeping my job?"

But is it also true, as his campaign literature suggested last Friday, that his leadership is most likely to save the seats of many Tory MPs in marginal constituencies? A telephone poll of 1,002 adults, carried out by Mori/On-Line for the Economist last Monday and Tuesday, suggests not. The best hope for the Tories (see table) is probably Michael Heseltine, while Mr Redwood is probably the worst prospect.

If there had been a general election last week - and it must be emphasised that public preferences could be quite different in 23 months or even in one month - Mr Heseltine would get three per cent more support than John Major and thus save the seats of some 52 Tory MPs. Michael Portillo, Kenneth Clarke or Gillian Shephard would get two per cent less than Mr Major and so lose 46 more seats than he would; Mr Redwood would get three per cent less and send another 18 of his Tories to electoral oblivion.

The 52 Tory MPs who might be saved by a Heseltine leadership include such Cabinet ministers as Virginia Bottomley and David Hunt as well as the 1922 committee chairman, Sir Marcus Fox. Another possible Heseltine "save" would be Allan Stewart, whose "marginal" Eastwood seat, is actually the safest held by any Tory in either Scotland or Wales and whose survival would save the party from a total Celtic wipe-out.

It may be argued that such "trial heats", as they are called in America, are hypothetical, and so they are. But they are the best way of probing, with a sample of real people, how they feel about a contest confined to an exclusive Westminster club. It may also be argued that boundaries are due to be changed later this year in two-thirds of the country. So some seats now marginal would be safe while others now safe would be vulnerable. But the overall numbers of Tory seats at risk would be similar.

So to which voters do the different candidates appeal? Compared with Mr Major, Mr Heseltine does better among men, among younger people, among working-class people and among those living in the Midlands and the North. He would hold 92 per cent of the Tory "loyalists" - those who voted Tory in 1992 and say they would still vote for a party led by Mr Major now.

Mr Portillo has a strong attraction for women and for people living in the Midlands. He would hold 86 per cent of the "loyalists". His principal weaknesses are with electors over 35 and with southerners.

Mr Redwood would hold 85 per cent of the "loyalists". But he would do much worse than Mr Major among older electors, the middle classes and southerners. Kenneth Clarke would hold nine in 10 of the loyalists; he is weak among women and older people. Mrs Shephard's supporter profile, although weaker than Mr Major's, is much the same as his; she would hold 91 per cent of the loyalists.

What of Europe, the issue that most strongly divides the candidates? Here there is a real surprise. Three in 10 of the public say they would favour Britain getting out of the European Union altogether. Yet the pro- Europe Michael Heseltine has more support among this group than any of the other candidates. Four in 10 of the anti-Europeans say they would support him; a third or fewer would support any of the other candidates, including the Euro-sceptics Redwood and Portillo.

This suggests that the European issue is not that important to most Britons. According to a Mori/Times poll published on Friday, twice as many people say jobs, health care, education and law and order will help to determine their votes at the next general election as say the European issue will do so.

Another Mori/Times poll, on Thursday, reportedly brought great cheer to the Major headquarters: it showed a "recovery" in the Government's level of public satisfaction from 10 per cent to 14 per cent. The proportion satisfied with Mr Major was up from 21 to 28 per cent.

But 79 per cent were still dissatisfied with the Government's performance, and 64 per cent were still dissatisfied with how Mr Major did his job. Further, in the Mori/Economist poll, six in 10 people said that the five years of the Major government had been bad for the country and 55 per cent said his premiership had been bad for them personally. Sixty- six per cent wanted an immediate general election and there was still a Labour lead of 24 per cent.

The writer is chairman of Mori and visiting professor of government at the London School of Economics.