A previously unknown early artwork by David Hockney has been rediscovered in Kent.

The sepia landscape was brought along to show the experts at Belmont House, outside Faversham where it was valued at around £30,000.

The owner, who has not been named by the BBC, hid his face behind the painting in shock when the programme’s art expert made his valuation.

The Antiques Roadshow’s expert Rupert Maas was astonished to discover the work was a Hockney, who is best known for his pop art depictions of Californian swimming pools.

The painting in question showed an English countryside scene and was sold by Hockney to a railway signalman near Felixstowe in 1957.

Kept in the family, the Hockney was brought to Belmont House by the signalman’s grandson.

The owner described his grandfather meeting the young Hockney and his friend, saying: “He noticed their equipment so he invited them into the signal box to have a cup of tea,

"He eventually invited them home for Sunday lunch because they were living in straitened circumstances.

"He said 'oh, bring a painting' and [grandfather] Wallace bought a painting from each of them.

"A year later, he brandished a piece of paper showing one of these guys [Hockney] had won the gold medal from the Royal College of Art.”

Mr Maas said he was "initially incredulous" that the piece was genuine but after researching the artist’s background found that the grandfather’s story was plausible.

He said: “It was a gradual dawning to a sparkling revelation by England's greatest living painter.

“He offered him Sunday lunch, it's the most extraordinary story."

Locals flocked to the 3,000-acre estate last August with objects for valuation, including a Take That trophy and the telegram announcing the end of the Second World War.

Specialists were on hand to examine family heirlooms and household treasures and offer free advice on whether visitors were sitting on a goldmine.

This is the first time Belmont House, which has been in the Harris family for five generations, has been visited by the Antiques Roadshow crew.

The house and gardens in Throwley encompass a cricket pitch, orchards and surrounding farmland and woodland.

The historic home is no stranger to antiquities, itself hosting collections of armour and weapons, works by the Trinidadian painter Cazabon and a museum of clocks.

More than 340 timepieces are on show at the 18th century house, which is dubbed one of Kent's hidden gems.

A spokesman for Belmont House said: “On a very warm summer's day last August, the Antiques Roadshow crew rolled into Belmont.

“Returning to Kent after several years and with many thousands of people applying for tickets, we were very excited to see the cameras start rolling.

“Visitor numbers on the big day exceeded all expectations and there was every kind of object carried in baskets, bags and pulled in trolleys, teddies to totems, clocks to crowns, swords to spears and lots of everything in between.

“A selection of objects from within the House were also looked at by the experts.

“It was a long and tiring day for all of us at Belmont House. Staff and our lovely volunteers worked really hard to make it a complete success.”