Politics gets more and more unpredictable. The state buys up banks. A dead prime minister issuddenly very much alive. I didn't expect to be writing about luxury yachts when the week began, yet I have probably written the word "yacht" more times in the past few days than ever before.

First there was the allegation that George Osborne sought funds for the Conservative Party from a Russian oligarch whose hospitality he enjoyed on the man's luxury yacht in Corfu. Then came yesterday's story that David Cameron enjoyed drinks on Rupert Murdoch's yacht, off a different Greek island, before adjourning for dinner on a boat owned by Mr Murdoch's son-in-law.

There is no evidence so far that the shadow Chancellor or the Tory leader broke the rules. But thesestories matter. Their real significance is that they may revive invoters' minds an image of the Conservative Party that the two men have worked so tirelessly to erase in the past three years. Timing is all, and this is a bad time.

Senior Tories insist the squalls will blow over and soon be forgotten. They admit that Mr Osborne was foolish to be present at a discussion of a possible donation from Oleg Deripaska, but say naivety and curiosity are not crimes. But what worried Tory MPs most was that these reports emerged in a week when both the Governor of the Bank of England, Mervyn King, and Gordon Brown used the "R" word – recession – and yesterday's official figures showed worse-than-expected negative growth of 0.5 per cent in the past three months.

Mr Cameron and Mr Osborne were already worried that their privileged upbringing, and their party's traditionally close links with the City of London, would make the public associate their party with the bailed-out bankers. This week's eventsreinforce the problem. "Cameronand Osborne are paranoid. The last thing they want is to look like fat cats," one senior Tory told me. "The timing is just bloody awful."

Some Tories took a comfort of sorts from the fact that many voters now regard all politicians as sleazy and on the make. They point out that the ubiquitous Lord Mandelson popped up in most of the stories about gin palaces, luxury villas, parties and high living off the Greek islands. They predict that that the public's response would be to say "a plague on all your houses", knowing that parties blame the media while drip feeding it with tit-for-tat allegations which lower the standing of politicians as a whole.

Perhaps it would matter less if we weren't entering a recession, and if Tony Blair were still prime minister. He, too, had a taste for the holiday high life. But you won't find Mr Brown taking freebies from Cliff Richard or Rupert Murdoch's son-in-law. As in the financial crisis, his dourness becomes a strength, not a weakness; an austere prime minister for hard times, while the country's would-be rulers mess about in boats. A serious party runs the country while the opposition party just parties. Such images are unfair, but they can stick. Remember William Hague's baseball cap.

All the same, old-guard Labour MPs who are cracking open a beer bottle shouldn't let it go to their heads. There are some who believe the new political landscape will enable Mr Brown to relaunch the class war for which many of them pine. The part-nationalisation of three banks has put a spring in their step. Some call for state ownership of the housebuilding industry. They believe the Tories' vision of a smaller state is redundant after the banks' rescue. They hope the Government's embrace of Keynesian fast-trackpublic building projects will befollowed by tax hikes for the rich.

I suspect they will be disappointed. Mr Brown has always loved market forces less than Mr Blair. Yet he will probably buy Lord Mandelson's statement to the Blairite think-tank Progress that New Labour's guiding principle remains "markets wherever possible, government intervention wherever necessary".

The Prime Minister wants toportray Mr Cameron as a wolf in sheep's clothing – but on policy, not personality. When Labour slipped into class warfare in the Crewe and Nantwich by-election, the voters were not impressed.

In any case, Labour doesn't need to reopen the class war. For the moment, at least, the Tory leadership is doing a pretty good job of reminding people about their backgrounds. Those photographs of the hell-raising Bullingdon Club at Oxford University are probably worth a million Labour posters.

If Labour lurches into class-based attacks, it would turn off the voters even more than the Tories have done in the past week. Mr Cameron is right to think that what matters to most people is "not where you come from but where you are going".

Yet the lesson for the Tories isthat they need to be very careful,as voters take a much closer look at them over the next 18 months and wonder how – and for whom – they would govern the country. You can't choose your parents, but you can choose your friends.