“Buyers of residential estates are drawn by both their hearts and their heads – living in a slice of Downton Abbey comes at a hefty price but when you consider the financial benefits the maths adds up.”

Knight Frank, the estate agency that advertised Ms Hurley’s property, said the average value of farmland had risen by 10 per cent over the past year alone.

Meanwhile, prices for prime residential property in London have started to slow – particularly since stamp duty tax increases in December. Prices in areas such as Mayfair and Kensington grew just 2 per cent in the year to June, the estate agency said, down from an 8.1 per cent annual growth rate recorded a year ago.

Looking back over the past decade, the near-200 per cent increase in farmland prices made for a highly-lucrative investment compared to the main alternatives. Buying shares in the FTSE 100, for instance, rewarded investors with average returns of 40 per cent over the same period.

^{Liz Hurley’s Cotswold home (Graham Norwood)}

Ms Hurley, famous for films such as Austin Powers: International Man of Mystery and Bedazzled, as well as modelling work for Estée Lauder, was dating her future husband, Indian businessman Arun Nayar, when she bought her farm in the Cotswolds. She used the land to produce organic meat, which was later sold at Harrods.

The property is located at the end of a long drive and has picturesque countryside views. In total, there are nine bedrooms, six bathrooms, a drawing room, dining room and sitting room.

On top of the main house, there is a guest cottage, a first floor flat, various outbuildings and even a party barn.

With prices high following her split from Australian cricketer Shane Warne in 2013, Ms Hurley last year put her stone farm on the market at £6 million.

It failed to generate any interest until the actress, currently starring in the US television series The Royals, added an extra 300 acres, taking the total to 410, and increased the price.

Mr Pryor said: “The wealthy have always been attracted to the ‘Brian Aldridge’ Archers lifestyle and Ms Hurley has clearly been well advised.

“She has added land to the estate as it became available to help ensure it is commercially viable.”

The home has been sold to a farming family and represents one of the biggest sales of year outside London.

Ms Hurley can now focus attention on her other country home an hour up the road near Ledbury in Herefordshire. She bought Doddington Hall in 2012 with Mr Warne, at the time her fiancé, for £6 million and bought out his half when they split a year later.

dan.hyde@telegraph.co.uk