A guest on BBC One's Antiques Roadshow was astonished to learn the enormous value of a centuries-old pistol he brought in on Sunday's episode. 

He had not spent a single penny on the 'astounding' display weapon, which was given to him by his stepfather who 'wasn't interested' in what what meant to be a gift for him.

The show's expert Robert Tilney was impressed by the gun's 'highest possible quality', especially after learning it had been 'dry fired' and broken in the past.

'This is a top quality presentation piece,' Mr Tilney remarked, before detailing that it was most likely from the 170s or 1780s.

He then took viewers through the gorgeously intricate design of gold and silver running down the barrel of the pistol.

A guest on BBC One's Antiques Roadshow was astonished to learn the enormous value of a centuries-old Italian pistol (pictured) he brought in on Sunday's episode

The display weapon was dated around the 1770s and 1780s, and given a £15,000 to £20,000 valuation

The show's expert Robert Tilney was impressed by the gun's 'highest possible quality', especially after learning it had been 'dry fired' and broken in the past

Beginning with the double-barreled muzzle, which was embossed with a 'fabulous' burst of gold at the point from which the weapon fired, the expert continued: 'Here, gold chasing [running his finger towards the sight].

'The two cartouches are the Turin proof marks. This is silver inlay work of the finest possible quality - a superb lion mask here with gilt round it.'

Mr Tilney then disclosed what he would expect to see such an item fetch at auction - a breathtaking £15,000 to £20,000. 

At first, its owner could only muster a 'wow'. 

'It's just a fabulous piece,' the expert added. 'Not something that a small boy should have played with, but we'll forgive you - it's wonderful. Thanks so much for bringing it in.'

The owner had described how the Italian pistol had been given to him when he was a teenager, and it had since been through the wars - albeit only metaphorically.

His stepfather had been given the gun as a present by a business partner, but 'later on, he wasn't interested, so I received it from him'.

Mr Tilney ran down the 'fabulous' designs embossed onto the barrel to two cartouches denoting that it came from Turin, Italy, seen at the bottom of the image

Antiques Roadshow: The most expensive items ever on the BBC One show

Fabergé Flower: £1,000,000 

Colonel Stamford Cartwright sent the show's jewellery expert Geoffrey Munn's pulse racing after bringing in a gold, diamond and jade flower ornament in April, 2018 - an expensive 'part of the furniture' piece.

The precious object was originally owned by the Queen's Own Worcestershire Hussars in 1904 by Georgina, Countess of Dudley, the wife of Lord Dudley.

It was brought in by Stamford, who took the object in on behalf of the squadron, known as B (Staffordshire, Warwick and Worcestershire ) Sqn The Royal Yeomanry.

The rare object showcased in a crystal vase was one of only 80 remaining ornaments of its kind.  

Angel of the North sculpture: £1,000,000

This rusty, man-sized model is worth more than the real Angel Of The North.

The bronze sculpture, which was brought on the show by John McElroy in 2008, was worth more than Gateshead council paid for the actual statue - which was a sum of £800,000.

Antony Gormley's piece was one of several created by the artist in a bid to persuade the council to commission the actual 66-foot statue in the 90s.

But the councillor revealed that his roots with the maquette run deeper than just being a part of the council.

His father worked in the coal mine where the full-size statue stands.

When the show's expert art dealer, Philip Mould, saw the piece at the Sage Centre in Gateshead, he revealed another model twice the size was sold recently for around £2m.

FA Cup: £1,000,000 

The longest-serving FA Cup trophy was brought on to the BBC show by Gabby Logan and Leeds United's former manager Eddie Gray in 2015.

And it wasn't until silver expert and football aficionado Alastair Dickenson revealed its eye-watering value that the two sports enthusiasts knew what they were in for.

The valuation, made at the Royal Hall in Harrogate, North Yorkshire, was the highest amount ever offered by Alastair after it was valued at £1,000,000.

Explaining the significance of the cup, Gabby revealed that the trophy had enjoyed one of the longest tenures of any sporting award, having been used for 81 years until it was finally replaced in 1992.

Alastair claimed the trophy's design suggested it had not been created to be a football trophy, and was more likely designed as a 'wine or champagne cooler' as it featured engravings of grapes and vines.

The trophy was created in 1911 by Fattorini and Sons, Italian immigrants who came to Britain in the late 19th century.

Jardiniere by Christofle: £560,000 

Terry Nurrish was stunned when this wedding gift - often commandeered as a goalpost by his children - was valued at £10,000 on the Antiques Roadshow in 1991.

But the retired farmer decided to keep hold of the antique for just a little longer and it turned out to be a wise decision.

It sold at auction in 2014 for a staggering £560,000, making it one of the most expensive sale prices of any item valued on the long-running show.

Terry, 68, was given the 'jardiniere' by his parents, who picked it up as part of a £100 'job lot' of antiques in 1946.

Unbeknownst to the family, it was a French 'Japonisme' enamel and bronze ornament made in 1874 by the renowned Christofle for the Paris Exhibition.

Mobile Lovers by Banksy: £403,000 

A boys' club that had a rare piece of Banksy artwork left on their front door had it valued on the Antiques Roadshow for over £400,000.

The work, called Mobile Lovers, had appeared overnight on a plank of wood screwed to a wall close to the Broad Plain Boys' Club in Banksy's home town of Bristol.

Dennis Stinchcombe, from the club, became involved in a row with the local council after removing the artwork put on  a wall near the club.

Struggling, they hoped that by selling the piece could keep them open.

But the artwork was removed by the city council, who maintained they owned the wall and put it on display in Bristol.

The artist waded into the argument by writing a letter to the club's owner, giving him his 'blessing' to do what he felt was right with the art.

Dennis, 58, then had the piece valued by experts from the Antiques Roadshow, who were filming in Bristol in 2014 and gallery owner and expert Rupert Maas told him selling the artwork for £400,000 would be a 'good deal'.

He eventually sold it at auction for £403,000.

Antony Van Dyck painting: £400,000 

It was an ancient treasure that could have seen one lucky priest £500,000 better off.

The Old Masterpiece, painted by Antony Van Dyck, was bought by Derbyshire priest Father Jamie MacLeod from an antique shop in Cheshire for £400 in 1992.

Spotted by presenter Fiona during the roadshow in Nottinghamshire, who was making a programme about the artist at the time, the piece was questioned as an original in 2013. 

When expert and art dealer Philip Mould and Dr Christopher Brown examined the painting, it was confirmed to be an original.

The piece is said to be called The Magistrates of Brussels, which hung in the city's town hall until it was destroyed by a French attack in 1695.

After a three-month lengthy restoration and verification process, the 17th-century painting was confirmed as an original as '17th Century brushstrokes beneath' the top layer of the painting were unveiled.

Gold Leica Luxus II Camera: £320,000 

A gold-plated Leica Luxus II camera was valued between £300,000 to £800,000 after it was brought on to the show in 2001.

It was originally valued at £5,000, but in 2013, it was put up for sale through Bonham's auction house and was revalued at upward of £300,000.

Encased in lizard skin, the piece is one of just four special edition versions made in 1932 and the whereabouts of the others remains a mystery.

The camera was given to its late owner, a keen amateur photographer, after World War II and used it throughout the 1940s and 1950s.

The Luxus II was used avidly for several decades and then put away until the owner took it to the show for a look-see.

When it went up for sale it was sold in Hong Kong in 2013 for £320,000.