Police investigating a cache of lethal DIY shrapnel bombs believe more of the devices could be buried in Oxfordshire, writes Tim Hughes.

Eight "sophisticated" explosive devices were uncovered in the grounds of Eynsham Park at Freeland, near Witney, over the weekend.

Officers said they were probing the possibility that the bombs could have been part of a racist plot to blow up today's Notting Hill Carnival, in west London.

Officers have urged the public to be vigilant.

The hoard was discovered by a man walking his dog through the estate a former Thames Valley Police training centre on Friday. They were made safe over the weekend by an Army Bomb Disposable team from Didcot, and taken to a forensic laboratory in Kent. The devices were packed into clear plastic mineral water bottles, each containing a quantity of explosive and about 3kg of new brass nuts. Some were fitted with complex anti-handling mechanisms, calculated to kill or maim anyone who tried to pick one up. Some are also thought to have been fitted with timers.

An identical device was found on a stone wall 30 miles away, near the village of Syreford in Gloucestershire a week earlier, prompting fears that a highly organised terror group may be operating in the area.

Thames Valley Police have described the latest find as extremely lucky, and believe a major terrorist offensive could have been foiled.

Det Supt John Donlon, of Thames Valley Police, said officers were collaborating with the anti-terrorist branch, and were looking very closely at the possibility that the bombs were meant for the carnival. Threats to bomb the event had been made to organisers by a fascist group calling itself The Blackshirts.

Because of things which have been said during the week to the promoters of the carnival, that is one thing we are looking at, among others.

Det Supt Donlon, who is leading the investigation, said detectives were also looking at links with animal rights activists, but he stressed this was only one of many avenues of inquiry and he was keeping an open mind. Officers have dismissed suggestions of a plot to bomb Home Secretary Jack Straw, who has a weekend home at nearby Minster Lovell. Det Supt Donlon said the bombs were designed to inflict horrific injuries. He said: "These devices are, in the opinion of our experts, extremely sophisticated and extremely dangerous.

"We hope we have found as many items as were hidden and have stopped a campaign. But we want to make the public aware of how dangerous these devices are and ask that anybody who finds anything similar to these in suspicious circumstances contact the police on 999 immediately." He urged local people and retailers to come forward with information about the find. He added: "We are keen to trace anyone who may have seen any suspicious activity in or around the area of Eynsham Hall or anyone who may have information which could assist us with this inquiry to call us. In particular we would appeal to retail outlets which sell brass nuts to contact us if they have sold any in large quantities in recent times."

Information can be passed to police on 01295 754610.