A rare police water cannon built to tackle rioting in Northern Ireland has been auctioned.

A 26-tonne riot control lorry built at the height of The Troubles to deploy a water cannon is set for a new home after being bought for just £3,100 in an online auction.

But as the 1970 Foden hasn’t had one careful owner, the dents won’t polish out and a big restoration will be needed.

The six-wheeled vehicle, believed to be the only one left in existence, was sold by a military vehicle restorer who bought it from a museum.

It was hurriedly commissioned by the Northern Ireland government for the Royal Ulster Constabulary as community relations rapidly fell apart.

Eight vehicles were deemed to be needed, of which four were borrowed and modified.

The contract for the remaining four went to Foden trucks and Pyrene, the fire extinguisher company.

A 10-tonne lorry chassis was shortened and strengthened to be able to take the weight of the water tank and the Coventry Climax engine used to pump it – plus the additional protective steel body, underside and mesh window guards.

Fitted with a six cylinder diesel engine, four vehicles were completed over two years. Two were delivered in 1971.

But they turned out to be a damp squib: at anything other than close range the hose had so little impact that children were filmed dancing in the spray.

One idea floated was to add a dye to the water to help identify rioters who could then be arrested. Another proposal was for an irritant to be added.

But the situation was rapidly deteriorating with a sharp increase in terrorist atrocities meaning the unarmoured vehicle was itself a target.

The Northern Ireland government changed tactics and the Army was sent in leaving the vehicles largely redundant.

The contract was one of the last commissions for Pyrene which was famous for making fire extinguishers and airfield fire tenders. The firm was taken over by fire safety and locksmith firm Chubb and ceased trading in 1971.

Foden too is no more; the truck firm was bought out in 1980 and ceased production in 2006 after 150 years of manufacturing.

Little of the vehicle’s history is known after its stint with the RUC - or what happened to the rest of the fleet.

Still painted in regulation green, it was passed to the Museum of Army Transport in Beverley in Yorkshire and remained on display until it closed in 2003.

The Foden then ended up at an outdoor museum collection in Humberside before being bought on the spur of the moment by military vehicle restoration firm Allsops of Bolton as a non-runner.

The COVID-19 outbreak delayed its arrival at the firm, run by three enthusiasts, but due to having too many other projects, the Foden was put up for sale.

Director Jonathan Allsop said: “We were buying other stuff at auction and we have the equipment to move it. It was an impulse purchase. I had never seen one before.”

It’s also like to remain a rarity as Northern Ireland is the only part of the UK to have used water cannons. Newer vehicles were most notably deployed in Drumcree in 2000.

The Metropolitan Police briefly had two on its vehicle fleet after Boris Johnson, when he was London Mayor, bought a pair second hand from Germany in 2014.

They cost £322,000 to purchase and a further £32,004 was spent on low emission zone compliance. A £23,000 paint job and nearly £1,000 was spent on communications kit.

But the Met quietly made clear they were uncomfortable with the purchases. Then-Prime Minister Theresa may announced a ban on their use in 2015, rendering them useless.

The vehicles were mothballed at an East London depot before being sold for scrap for just £11,025.

Current Mayor Sadiq Khan said "we have managed to finally get rid of them".

The Foden is now likely to be restored and will be sought-after by military vehicle enthusiasts. The market value, when finished, will be around £20,000.

A small number of RUC Snatch Land Rovers have made their way onto market and are worth around £15,000.

Mr Allsop added: “It has restoration potential and to be quite honest it should be restored.”