THE FIRST time I went to The Lansdowne, angling for an under-age pint in 1985, a traffic warden came into the pub, passed over the niceties of community policing, and launched into a topless rendition of "Knees Up, Mother Brown". The birthday boy put a condom on his head and blew it up from inside, so that he looked like Astrosmurf, and then buried his head in the traffic warden's breasts and wept at the fickleness of time. Suddenly, there was more to passing yourself off as a man than asking for a pint of Greene King without a giveaway croak.

A few weeks ago, a woman I had often seen on TV complained at the bar that the basil leaves garnishing her tagliolini had been cut, rather than torn, thus inhibiting the flavour. It was, begged the barman, a rare aberration.

Baring its Victorian tiles to the junction of Gloucester Avenue and Fitzroy Road, The Lansdowne used to be in Chalk Farm. So did the Pembroke Castle, the Queen's and the Princess of Wales. Now they are all in Primrose Hill.

The orange carpets and PVC banquettes have gone, like the Irish and Scottish working class of that part of NW1. Now wooden floorboards, chunky tables and leather sofas accommodate media folk, hungry for gossip and focaccia, who wouldn't be seen dead in a pub.

People used to be seen dead at The Cow in Westbourne Park. Or, at least, new home-owners kept away for fear that they might be. It was revamped two months ago by Tom Conran to cater for the trendy overspill from Ladbroke Grove. Now the barman talks of the days when this was a "heavy" pub and catered for the "slums". Guinness is pounds 2.15 a pint and represents 80 per cent of the pub's gross, "because of its association with oysters".

As at The Lansdowne, wood has been used to stand for something intangible (presumably taste). There are vast chairs hewn from beer barrels and charming olde-worlde lino. For customers new to the complexities of pub life there is a helpful sign: "Please order and pay at the bar."

If the Lansdowne is self-conscious and twee, The Cow is utterly ridiculous. It is no more a pub than it is a four-legged ruminant called Daisy. I can only sympathise with residents who bemoan the loss of their local. It is yet another misery being heaped on the old city. As once undesirable postcodes fall prey to trendification, the homogenising demands of fashion are destroying the only institution which makes London different.

But there are some things even a Conran cannot predict. A man wearing a Rolex suggests that the designer dream has worked swiftly. TV presenter? Fashion designer? "No, that lot are gangsters from the East End," says the barman. "They come for the seafood. They were good for a grand a week in the last place I worked." The last place?

"Bibendum," he said.

Must be one of those fancy pubs down south.

! The Lansdowne, 90 Gloucester Ave, London NW1; The Cow, 89 Westbourne Park Rd, W11