Hardwick Park was recently elevated by a £10m restoration, which goes some way towards explaining it's unusually good condition

SWALLOWS swoop along the Serpentine River and a seagull lands on Neptune's head. A kestrel performs an acrobatic roll over the crown of the Roman god of water, scattering the other birdlife, before disappearing over the tower of the Gothic ruin .

A group of mallards babble up the steep bank and gather at the buckled feet of 18th Century architect James Paine, hoping for rather more than the historic morsels that come tumbling from his lips.

"Alexander Pope said 'all gardening is landscape painting', and that's what this is, " says James, shuffling his shoes so he can take in the view, causing the ducks to move. "It is just like a landscape painting hung up."

James Paine is the designer who created the extravagant landscape at Hardwick Park, on the edge of Sedgefield . Mr Paine's park has been fortunate in that after a century of neglect, its owner, Durham County Council, spent £10m restoring it in the first decade of the 21st Century, before council cuts began to bite. As a result, Hardwick is now one of the finest 18th Century landscapes in the country.

Although Mr Paine died in 1789, he is brought to life every Tuesday afternoon by Michael Rudd, the chairman of the Friends of the park.

Michael, a former Geography and IT teacher at Darlington's Carmel School, gives free guided walks dressed as Paine in breeches and a frilly shirt, and he transports his walkers back to the 1750s when the designer was beginning his work. Paine was engaged in 1754 by John Burdon, a barrister whose father had been a well-to-do entrepreneur, big in salt-pans, in South Shields .

Burdon is an enigmatic figure.

A bachelor, he built up a mineral empire of coal and limestone across Durham and Northumberland , which extended into property, banking and agriculture.

In 1748, he bought the medieval manor house at Hardwick, and its estate of fields which included a spring-fed bog; in 1755, he added the 1,000-acre Coxhoe estate.

And then, around 1790, something happened. No one quite knowswhat, but his fortunes turned. He sold ostentatious Hardwick, and quietly slipped away. . .

So let's join his architect, James Paine, at the new visitor centre and, with Michael Rudd's help, look at what the pair of them were creating 250 years ago:

SERPENTINE RIVER

The snaking stream is filled naturally by springs which previously had created a bog.

Itwas inspired by the artificial lake of the same name that Queen Caroline had had created in 1730 in Hyde Park, London. The royal interest sparked a fashion among the nobility for creating extravagant parklands inspired by what they had seen on their Grand Tours of Europe.

STATUE OF NEPTUNE

The Roman god of water, seen conquering a dolphinwith his trident, stands on a small island in the Serpentine. The statue was originally made in lead by the fashionable London sculptor John Cheere. It cost £32 12s, including carriage to Sedgefield, but itmysteriously disappeared in the 1940s, and the recent replacement cost £30,000. It is believed to be the same design as the Neptune in Durham Market Place.

GOTHIC RUIN

The turreted fake ruin contains the oldest masonry at Sedgefield: Part of it is a gatehouse, built about 1120 by Durham Cathedral masons, that Burdon had transported from Gisborough Priory in Guisborough .

BANQUETING HOUSE

Ona rise overlooking the whole park was a Banqueting House, filled with classical busts, plasterwork and paintings. Our guide, James Paine, says: "As you know, a banquet is an entertainment after the main meal in the hall. It is a course of sweetmeats, fruit, and wine, usually in a different room - in our case, this house. There will be some music, I expect, for Mr Burdon's guests."

The house was in the Palladian style, and it is thought that Paine designed as a small wing of a grandmansion that Burdon planned as a replacement forHardwickHall.However, his change in fortunes thwarted his plan.

The house no longer exists, although its pillars and lintels were used in the 1940s to build a cinema in Front Street, Trimdon Village. It became a clothing factory before it was demolished in 2001, although the pillars are now in storage waiting one day to be turned back into aBanquetingHouse.

GRAND TERRACE

The unseen Serpentine River feeds Hardwick's lake in front of the hall (now a hotel). Burdon's guestswould have promenaded along the Grand Terrace beside the lake, sitting in either the Tuscan Alcove or the Gothic Seat to look over the extraordinary views: the tower of the Gothic Ruin could be seen tantalising between the trees; the Temple of Minerva as the focal point on its hillock in the near distance.

BATH-HOUSE

At the end of the Grand Terrace was a bath-house, of which only the footprint remains. Here Mr Paine becomes rather reticent about his master's plans. The bathhouse included two bedrooms, a plunge pool and a breakfast room heated by a fire. Mr Paine says that Mr Burdon liked a couple of cold immersions every morning before warming himself over breakfast; good old-fashioned gossip says that it was here in relative seclusion that Mr Burdon immersed himself in the company of his lady friends.

BONO RETIRO

Concealed in a dip, this was a "place of pleasant retirement". "Here we shall have a library, with tea-making equipment, lit by stained glass windows, " says Mr Paine, grandly.TheBonoRetiro faces the cascade out of which the water in the lake flows on its way to the River Skerne.

TEMPLE OF MINERVA

Standing majestically on an open hilltop, the temple is dedicated to the Roman goddess of poetry, medicine, wisdom and war. Mr Paine explains that he based the temple of the mausoleum of the Roman Emperor Diocletian which he had seen at Split (now in Croatia) on his Grand Tour.

He says: "I expect Mr Burdon's guests will take tea here, perhaps play cards and, I am certain, will enjoy the views."

It is a panoramic hilltop, with the lake and Banqueting House on one side and the distant Pennine Hills on the other.

The temple's interior was elaborately decorated with busts of literary giants from Homer to Shakespeare, and of classical greats, from Socrates to Julius Caesar. There were images of the four Virtues (Prudence, Justice, Fortitude and Temperance), a mosaic floor, a grand ceiling painting ofMinerva and an inscription in gold: "This temple, began by John Burdon Esq, in the year 1754 and finished in 1757".

There is an enormous irony in Burdon spending a great fortune creating fake classical history in hisWest Parkwhen, unknown to him, beneath the fields of his East Park there lay a bona fide Roman settlement beside a genuine Roman road, whichwere identified by the geo-phys equipment of TV's Time Team in 2002.

GOTHIC BRIDGE

Dropping down from the temple, the pathswends back into the woods which shields the Serpentine River from view.

The bridge crosses the river, enabling the visitor to look down on the statue ofNeptune and up to the Gothic Ruin behind it. In Burdon's day, the Circuit Walk for local visitors began at an ornamental lodge house which is now beneath the A177. A gardener would meet them and guide them through the pleasure grounds.

Today's guided tour ends back at the visitor centre, which is at the centre of a very modern row - the council has just imposed parking charges for motor cars.

"You have seen a garden under construction in the latest style, " concludes our guide, Mr Paine. "It has an ornamental nature of peeps, paths and prospects."

With the mallards gathering at his feet, he finishes with a flourish, quoting the fashionable Alexander Pope in his translation of Homer's Odyssey: "It is a scene, where if a god should cast his sight, A god might gaze, and wander with delight!

Joy touch'd the Messenger of Heav'n: he stay'd

Entranc'd, and alll the blissful haunts survey'd."