A spectacular new Norfolk treasure has been unveiled - after years of being used as a doorstop.

The 3,500-year-old Rudham Dirk, a ceremonial Middle Bronze Age dagger, was first ploughed up near East Rudham more than a decade ago. But the landowner didn't realise what it was and was using it to prop open his office door.

And the bronze treasure even came close to being thrown in a skip, but luckily archaeologists identified it in time.

Now the dirk has been bought for Norfolk for close to £41,000 and is now on display in Norwich Castle Museum.

Dr John Davies, Chief Curator of Norfolk Museums Service, said: 'This is one of the real landmark discoveries.'

The dirk - a kind of dagger - was never meant to be used as a weapon and was deliberately bent when it was made as an offering to the gods.

Only five others like it have ever been found in Europe - including one at Oxborough in 1988, which is now in the British Museum. But thanks to a £38,970 grant from the National Heritage Memorial Fund, following a £2,000 donation from the Norfolk and Norwich Archaeological Society, the Bronze Age treasure will now stay in the county.

Dr Tim Pestell, who is Curator of Archaeology with the NMS, has been negotiating with the (unnamed) landowner for almost a year. He said: 'As soon as my colleagues told me about it we started to plan how we could acquire it, so it could stay in Norfolk and be on display here.'

Dr Andrew Rogers, whose team first identified the dirk, said he never expected the Oxborough discovery would be repeated. 'It's absolutely incredible. Gosh - to have a find like this twice in a lifetime - this is unbelievable,' he said.

The 1.9kg (4lb) dirk is made from bronze, which is nine-tenths copper and one-tenth tin. The nearest source for the copper is Wales, while the tin may have come from Cornwall.

Straightened out, it would be 68cm long, slightly shorter than the Oxborough example. It may even have been made in the same workshop, maybe even by the same craftsperson.

Sophie Cabot, president of the Norfolk and Norwich Archaeological Society, added: 'We're really excited - it would have been a great shame if we'd have lost it.'