London's front gate in a brewer's backyard

For this Hertfordshire walk, I started in a little known corner of the London Borough of Enfield which has a country feel. Indeed several London street maps omit the little known village of Bulls Cross.

Long before the Pied Bull pub began serving visitors in 1790 it was the kennels for hounds hunting across Enfield Chase. One beam is permanently wrapped in padding to save the heads of customers who don't know the history. More recently the pub was the childhood home of garden writer Frances Perry, who later lived a couple of doors away at Bulls Cross Cottage. A little further along the road is Myddleton House, where the garden of the legendary horticulturist E A Bowles is being restored.

But it is still too early for springtime garden visits so I turned north from the pub up Bulls Cross. This is a surviving section of the Roman road Ermine Street. Pedestrians can continue ahead on the ancient route by ignoring the bend and going down Gilmour Close to pass a now lonely lodge cut off from Theobalds Park by the M25.

The detour is by way of a gate, stile, and a scramble up a bank. But for once the old GLC boundary and the new motorway boundary coincide, so the bridge takes us not only over the motorway but out of London into Hertfordshire. The drive is the Roman road leading now, not to Lincoln, but to the Abbey National conference centre. It was the grand home of 19th-century brewer Sir Henry Bruce Meux who married the barmaid at his Horseshoe Tavern in Tottenham Court Road.

Keeping to the left of the great gateway I took the road round the park to a junction with Temple House and then along Old Park Ride to pass Gardener's Cottage. Winter is the best time to walk this track for as the way begins to run gently downhill the still bare trees expose the outline of a stone building.

This is Temple Bar, maybe designed by Sir Christopher Wren, which certainly for over 200 years was the ceremonial gateway to the City of London. This impressive City boundary-marker spanned the road behind St Clement Danes Church, where the Strand becomes Fleet Street. In 1877 it was an early casualty of London's traffic problems and the arch was taken down stone- by-stone in a yard off Farringdon Road.

It was Sir Henry's upwardly mobile wife who thought the redundant gateway would make an impressive back gate to the estate. It has now been here for just over a century becoming more and more dilapidated and giving rise to occasional attempts to find it a home back in the City. The last suggestion was in St Paul's Churchyard.

Continuing past the front of Temple Bar I joined a newly metalled and widened woodland path known as Theobalds Lane which soon has another surprise. This is Tesco's staff playing field where those who work at the new TescoMetro back in the City's Cheapside can play at the weekends. Turning right, through a new and only partly installed kissing gate, one sees the Meux mansion flying the Abbey National flag.

The flowing water here is the New River which was new in the early 17th century when James I came to inspect the freshly dug channel and fell into the mud. The man-made river takes clean water from the River Lee before it becomes polluted by flowing down the parallel Lee Valley. The new direct route once led as far as Sadler's Wells from where the pure water was piped into the City. Thames Water is only now ceasing to make use of this handy source of country water following the opening of the new London Ring Main.

On the ridge beyond the Lee Valley are the trees of Epping Forest - London's back garden still maintained by the Corporation of London. Here, at the back of Theobalds Park, the New River is wide enough to have a rare island as it winds its way along the edge of the mansion's grounds. By crossing the footbridge and diving along the edge of the woodland it is possible to avoid the M25 and maintain the idyll.

Back at Bulls Cross the Pied Bull was still open. Where better than a 400 -year-old kennel in which to reflect on a walk which yields up a forgotten piece of the capital's heritage?

t Use OS Landranger 166 or A-Z Master Atlas of Greater London. Bulls Cross is just north of Forty Hill in Enfield. Trains stop at nearby Turkey Street Station (Liverpool Street-Broxbourne line) on weekdays and Saturdays. A version of this walk appears in Pub Walks in North London by Leigh Hatts (Countryside Books pounds 5.95).