Remember Back to the Future, the movie in which Michael J Fox plays a teenager who travels back in time to the 1950s? In the film, Fox's mission is to make sure his parents fall in love and get married, otherwise he won't get born, so he has every reason to take a proprietorial interest in the success of their relationship. On Thursday, when Tony Blair wrote himself a starring role in the Queen's golden wedding anniversary celebrations, I got the uneasy feeling that the prime minister was doing something similar - assuming the deferential attitudes of the 1950s, for a day at least, in order to shepherd his royal "parents" through a rocky patch.

The difference is that, in the wake of the death of Princess Diana, their long-term survival depends on him rather than the other way round. In the short term, however, the Prime Minister needed some good publicity and he certainly got it. In his speech congratulating Prince Philip and the Queen - whose reign, as we all know, has seen an unprecedented decline in the popularity of marriage - Blair acted the part of the approving son, using the occasion to let the oldies know how well they had done.

"My generation," he began at one point, as though he was about to launch himself into an a cappella version of the old Who song, but of course we didn't get anything so radical. Blair is in the business of cementing his position and he is not above reminding the royals how much they owe him for his face-saving interventions in the run-up to Princess Diana's funeral. "Hurtful things" had been said at that time, he acknowledged, sounding like someone who could not quite bring himself to refer to the disgraceful events, hair-pulling and name-calling, which had taken place at Great Aunt Maud's wake.

But that was all in the past. "My generation pays tribute to you today," he insisted, "with every bit as much force as older generations do. For you stand as our Queen for those values of duty and service which are timeless."

In return for this piece of shameless sycophancy, Blair was rewarded with endless photo opportunities in which the difficulties of the previous week - Formula One, Bernie Ecclestone, tobacco sponsorship of sport - appeared to have vanished like a bad dream.

EVERYWHERE the Queen and the Duke of Edinburgh went on Thursday, the Prime Minister was on hand, emerging with them from Downing Street to meet the people - an obligatory exercise for the royals in these post- Diana days - and sharing their walkabout outside Westminster Abbey after a service of thanksgiving. So was Mrs Blair, participating in another of those Take Your Wife To Work Days which have become a regular feature of the new administration - she always seems to be attending fashion shows, or leaders' wives' luncheons, or taking the day off to hold Tony's hand. (For a moment, I even wondered whether the Queen was being ironic when she addressed the Blairs "as one working couple to another" and looked forward to their golden wedding anniversary in the year 2030.)

It was altogether a very New Labour occasion - modern but traditional, as Blair himself pointed out. "I make a lot of this being a modern country," the prime minister said, genuflecting in the direction of the youth vote. "But contrary to myth, modernity and tradition can and do live happily together," he went on, ensuring the continued support of Daily Telegraph readers. As relaxed with Oasis fans as he is with retired majors, Blair's vision is new, old, modern, traditional, all at the same time. The Michael J Fox of politics, he revealed himself this week as our first time-travel prime minister, fired by a vision in which he effortlessly takes Britain back to the future - via the 1950s.

AS IF on cue, while Tony Blair was prattling on about traditional values, a spectre from 40 years ago came back to haunt us. Killer smog enveloped London's Docklands and the Evening Standard published an astonishing colour photograph of one of the city's landmarks, the Canary Wharf tower where this newspaper is produced, barely visible in a dense brown cloud of polluted air. People who suffer from asthma and bronchitis have been warned to take extra care in case they suffer breathing difficulties or even heart attacks caused by the pollution.

The Standard listed the six main pollutants responsible for the terrible air quality in London, including benzene, nitrogen dioxide and sulphur dioxide, and blamed them squarely on emissions from cars and lorries. In the United States, studies show that PM10s - soot deposits which settle in the heart and lungs - kill around 2,000 people in cities comparable to the size of London. One recent estimate suggests that poor air quality may kill 11,000 people a year in Britain.

This brings me to a philosophical problem which has been troubling me ever since the government got itself into such a mess over its proposed ban on tobacco sponsorship, and its exemption of Formula One. Cigarettes kill people but so do cars, even if their owners respect speed limits and drive them safely. Indeed it is much easier, in these days of smoking bans in offices and cinemas, to avoid tobacco smoke than it is to escape emissions from exhausts; even if I gave up my own car tomorrow, I would still be exposed to the deadly pollution from the half million cars which enter central London each day.

So why ban tobacco advertising and not the huge campaigns designed to persuade people to buy the bigger, faster cars which are choking us to death? Surely it would be more logical to ban Formula One as well as cigarette advertising, rather than allowing these two deadly industries to boost each other's dirty profits? As it happens, I'm not sure that the government should have embarked on this dubious course in the first place, given that cigarettes (and cars) are legally available products.

But that's an old-fashioned libertarian view, the kind of thing we don't want to hear about in Tony Blair's modern, traditional, 1950s Britain. Wait a minute, I'm getting confused here. What did you say the date was? I think I'll just slope off and get one of those beehive hairdos. No one can call me square.