Pastoral images of manor houses set in green fields and framed by fulsome oak trees is every Englishman's idyll.

A munificent - if slightly potty - lord overseeing a wizened but contented group of tenant farmers, and a jolly lot of household staff: Brideshead Revisited and all that.Reality, however, involves motorways, supermarkets and other commercial ventures, which spawn leases, franchise agreements and myriad other traps.

Then there are heritage management agreements and maintenance funds, in addition to taxation questions.

Potentially the sort of legal cocktail that would have driven Lord Marchmain to an even earlier grave.In short, the country estate of the 1990s has had to adopt the entrepreneurial spirit that swept Britain's business sector during the previous decade.

And expert legal advice is an essential requirement in ensuring that estate owners do not drown in the new competitive seas.Earlier this year, two leading partners in the agricultural estates team of London solicitors Fladgate Fielder transferred their talents to Salisbury firm Wilsons.

They took a few clients with them - including one duke and four earls.

The very cream of private client work.There are only a few firms the landed gentry turns to for expertise on running their estates - about three in London and increasingly Wilsons in the provinces.

But Wilsons is far from a typical country firm: more than half of its 17 partners started their careers with large City or other London practices, and they now act for clients whose combined total land tallies about 240,000 acres.

Indeed, some 40% of the firm's turnover is derived from work involving landed estates.

Its team of five dedicated partners acts for about 50 agricultural estates.Although for historical reasons - Wilsons can trace its Salisbury roots back to the early 18th century - most of its clients are based in the Wiltshire-Dorset area, the firm considers itself to be a national power.

The partners regularly travel to country estates in Yorkshire, north Wales and Norfolk.And just as farming the land has become increasingly complex over the last 20 years so too has owning the land.

'We have been forced into providing a much broader area of service,' explains Wilsons senior partner Anthony Edwards, himself a London transplant - from Farrer & Co - some 20 years ago.Essentially, the modern estate owner has to deal with two main factors which would have been completely alien to their relatively recent aristocratic ancestors: commerce and heritage.The former is the money spinner and it usually involves selling off bits of land to either the state or to private industry.

One Wilsons client recently made a substantial sum simply because the Department of Transport fancied a few chunks of its land for a new motorway.

Another in the west of England has struck a deal whereby 200 of its total 5000 acres have been sold to an industrial developer which is planning to build a Safeway superstore.Lawyers acting for landed estates also find themselves supervising contractual agreements between their clients and the National Gallery over long-term arrangements for collections of art.

And two of Wilsons clients have functioning oil wells on their land.On the heritage side, an entire area of law has grown up during the last decade relating to tax exemptions, management agreements and maintenance funds.

This, according to one of Wilsons' latest additions, ex-Fladgate partner Peter FitzGerald, is one of the most complicated areas of law.

And land owners can get it badly wrong.According to Mr FitzGerald, the most important heritage aspects relate to public access.

'I know of one or two cases where the estate has been crucified by over-restrictive provisions which have been agreed by the capital taxes office as a condition for exemption,' he says.

'It is quite possible to claim an exemption on one's land of outstanding scenic importance or one's stately home, which includes entire provisions for public access or the management of the land in restrictive terms, making it impossible for the estate to survive.'Dealing with that sort of conundrum is a specialised skill which Wilsons' lawyers maintain has given it a competitive edge.

Of the 75-odd maintenance funds agreed between government and landed estates, Wilsons acts for 12, while most of the others go to those few City firms.Another relatively recent development is the increasing trend for large English and Welsh estates to be owned by overseas-based landlords.

At Wilsons this brief now falls to partner John Emmerson, yet another former City lawyer.

Mr Emmerson used to head the private client department at McKenna & Co, with particular emphasis on contacts in the far east.Mr Emmerson now focuses on either ex-patriot or foreign landowners with property in the UK.

It is an area, he says, which is ripe with complications involving questions of tax, domicile and residence, and immigration.Negotiating the best deal possible for their clients brings Wilsons into direct and frequent contact with bodies such as the capital taxes office of the Treasury, the Countryside Commission, English Heritage and the Historic Houses Association, to name a few.

Quite naturally, the solicitors maintain that the required level of expertise is rare.The firm primarily views the City firms as its main competition.

'The average provincial solicitor does not have enough large agricultural estates on his doorstep to make it a specialist practice,' points out Mr FitzGerald.And while the City firms have the expertise, they also have the large fees.

Most traditional country estates still do not have large cash flows and, as Mr FitzGerald says, 'they can be absolutely crucified by professional overheads'.Wilsons reckons that its Salisbury base allows it to undercut London rivals by as much as 50% on cost, depending on the brief.Country landowners have become much more commercially aware and cost-conscious regarding professional services.

That change means that Wilsons partners frequently find themselves attending beauty parades when pitching for new clients.As Mr Emmerson points out, another force driving work out of London has been the increasing prominence of trusts which look after landed estates.

Wilson acts for several Channel Island-based trust companies of merchant banks.

'Even though they are used to paying large legal fees, they must take into account the fact that they are trustees for beneficiaries, and if they can get a really first class service out of London at half the price, then they have an obligation as trustees to do that.'