Britain is changing before our eyes. From 1 July, people will no longer be allowed to smoke in public places, as the ban is extended to England. Hunting has already been outlawed. For beagles, this represents a double whammy: the poor creatures now have few pleasures left. But there is a further development in the air: from 27 June, the date of his resignation, it will no longer be permitted to discuss Tony Blair in public. No longer will innocent people be subjected to others' views on the theme, or inhale their stale opinions. Pubs, clubs and offices will be transformed, as the air clears and the fog is lifted. Those sad addicts who cannot kick the habit will be forced to huddle under patio heaters on the pavement to indulge their craving. Already, in the Westminster village, helplines have been set up and special areas designated where lifelong Blair devotees can gather and discuss his legacy without fear of harassment.

For me it will be something of a relief, albeit a mixed one. In common with many Labour MPs, I disagreed with most of what he said, but was grateful that he kept me in work. When he became Prime Minister, I remember thinking "What do I do now?". I later realised he must have been thinking the same thing. As it was, through the twists and turns of his career, from the Bambi years - all smiles and seeking to please everybody - through the Alastair Campbell era to the grotesque error of Iraq and the surreal spectacle of his final weeks, where Britain has had a dual-fuel premiership, he has provided more material than one could ever imagine.

I wonder, as he looks back, what Blair makes of it all? What Dorian Gray picture there is in his attic to remind him of the difference between the fresh-faced idealist of 1997 and today's careworn practitioner of realpolitik. His speeches as opposition leader are certainly in marked contrast to the direction he later took. I think it's because, as Neil Kinnock has said, he was always impressed by money, by power and by uniforms. He sought to deal with the rich and powerful and ended up doing so on their terms. Likewise, in seeking to harness the power of the media, he ended up in hock to it, seeking "eye-catching initiatives" and becoming preoccupied with spin.

It will be hard for him to leave the big stage behind: I imagine that in the privacy of his bedroom, Blair is probably very good at playing "air prime minister". He must have loved shooting the breeze with Clinton and Mandela - even felt that when Bush came to power, he could be Bill Clinton to Bush's Blair - the wise, guiding influence of a more experienced, liberal world statesman. We know what happened to that dream. At least Blair can walk away from it all. I bet there are a few troops in Iraq who'd also like to get out just by handing over to their next-door neighbour.

He spoke only two words to me as Prime Minister. When I told him he was making our job too easy, he simply stammered "My kids!", which I took to be a reference to his kids doing impressions of me doing impressions of him. As it was, there was so much about new Labour that was beyond parody. Having in John Prescott a deputy PM who looked more like a National Express coach driver; Reid and Clarke, the home secretaries who moonlighted as night-club bouncers; Blunkett, the unlikely Casanova. The purring Mandelson, incapable of keeping his fingers out of the pie. Whatever else, they provided rich pickings as characters. Blair's departure continues a fire-damage sale at Westminster: a bonfire of the vanities, as all the colourful characters head for the doors. ("This deputy PM MUST GO! This shop-soiled home secretary, no longer fit for purpose! These former Tory and Lib Dem leaders, free to good homes!"). I look at the six candidates for deputy PM and despair. Perhaps they should have taken a leaf from Simon Cowell's book and run the deputy leadership contest as a week-long TV spectacular: "Labour's Got Talent!" Except there's one obvious problem with that. The title.

As I write, we really don't know that much about what Gordon Brown will be like. Will any members of his cabinet be recognisable? Is there a factory somewhere, even now turning out Miliband after Miliband on an assembly line, each indistinguishable from the other? Blair once said, "We campaign in poetry but we govern in prose." Will Brown go a step further? "We campaign in prose but we govern in morse code?" Such is our uncertain future. But at least it will be different. It is the end of an era. The Americans pronounce that as "error". Time will tell.

And what of the legacy? Northern Ireland and devolution are plus points, certainly, but all pales into insignificance beside Iraq. For the rest, will this PM be remembered for any great achievements? Or will he be like the fallen hero of antiquity in Shelley's poem:

"My name is Ozymandias, king of kings:

Look on my works, ye mighty, and despair!"

Nothing beside remains: round the decay

Of that colossal wreck, boundless and bare,

The lone and level sands stretch far away.