Apprentice Ben Nicholson thought he was in the firing line in his first week at work - after accidentally ordering a £2.7m battle tank.

Ben, 24, was looking for quotes for a water storage tank and was unaware his boss had slipped in a number for defence contractor BAE Systems.

So he rang the Newcastle arms factory and asked for a tank coated with bitumen.

A member of staff at the tank builder realised Ben was being wound up - and played along with the joke.

The youngster was horrified to receive an invoice confirming his order at the staggering price of £2,785,994.27.

The outline specification stated the tank would have attached weaponry but the letter from BAE Systems apologised for not being able to supply the tank with a bitumen finish - "because this would affect the camouflage".

Ashen-faced Ben, 24, of Blyth, Northumberland, took the letter to Nik Smith, his boss at Newcastle-based Gilwood Engineering, expecting to be handed his cards.

Business development manager Mr Smith said: "He was wondering what he had got himself into.

"He had been asked to price some water tanks but was taking longer over it than I would have liked.

"So among the other numbers, I gave him one for BAE.

"Someone at the other end of the line obviously realised he was being wound up and played along with the joke."

Ben, 24, said: "Apprentices are often sent out for sparks for the grinder or tartan paint but this takes things to a completely different level.

"When I first got through to BAE, I thought the person who answered the phone seemed confused.

"She told me they didn't do bitumen-coated tanks but I insisted that I had it on good authority that they did.

"At that point, the penny must have dropped and I was put through to another department and ordered my tank."

He added: "When the invoice came through, I nearly dropped dead with shock.

"Nik roared with laughter when I took the invoice to him.

"It was only then I realised I had been hoaxed."