A teen 'bomb squad' who alerted police to old army explosives in a north Norfolk beauty spot have discovered that the area is littered with rusting ordnance.

Residents across Holt heard a loud bang after RAF bomb disposal experts carried out a controlled explosion of the two three-inch mortars uncovered by the four teenagers on Holt Lowes.

The weapons are thought to have become exposed during major clearance work on the site, next to Holt Country Park, which is popular with dog walkers, twitchers, cyclists and others.

A trustee for the 25-acre Lowes, which is being restored as heathland, said he did not believe the area was dangerous, but warned the public to take sensible precautions.

Daniel Lock, 16, from Brinton, was exploring the area with fellow Fakenham High School friends Ollie Cook, Elliott Twiddy and John Peck. The site is thought to have been used by the army for training after both the first and second world wars.

The boys originally located one mortar, about two to three inches underground, using a metal detector, and dug it out with a spade, according to Daniel.

They had set it aside, out of the way of walkers, and returned two days later when they uncovered more close by and contacted the police.

'There are tail fins and other bits everywhere - hundreds of them. Some are on the surface,' he said.

Ollie, 17, from Briningham, said he was surprised that neither the police nor the RAF bomb squad which exploded the mortars had carried out a wider search of the area for other potentially-dangerous items.

'You can see stuff all over the place. I think we're heroes,' said Ollie. 'There are lots of dog walkers here and families with small children - if a child came across one of these things they might not realise that it could be dangerous'.

But secretary of the Lowes' trustees Simon Harrap said he understood it was extremely unlikely that the 60 to 70-year-old ordnance could be triggered accidentally.

He added: 'We don't believe there is a particular hazard. If anything was going to go 'bang', I would have expected it to have done so during one of the huge fires there have been there over the decades'.

Another trustee, local district councillor Philip High, remembered earlier incidents of ordnance being turned up and said he had played on two old tanks there as a boy.

Mr Harrap added that over the years a few items had been found but they were normally the tail fins, which were harmless pieces of iron.

'With the conservation work turning up the soil recently, we may find a few more if there is some rain,' he added.

He urged the public not to touch anything suspicious, to contact the police if they believed something could be dangerous and said no-one should use a metal detector on the Lowes without the trustees' permission.

Clearance work, which involved removing birch trees, gorse and leaf litter, finished on the site in March. Mr Harrap said work would begin again in September, after the breeding season, but would take place about a third of a mile further away.