A suburban house, a resident struck down by illness and the riddle of a radioactive garden

Ministers were accused last night of a "cover-up" over the existence of unnaturally high levels of plutonium found in a suburban garden.

Ministers were accused last night of a "cover-up" over the existence of unnaturally high levels of plutonium found in a suburban garden.

The existence in Roy Fox's Berkshire garden of levels of man-made plutonium 40 times higher than normal background radiation has made him question whether radioactive materials have been used secretly behind his home.

Mr Fox, 52, has abandoned his detached house at Earley, near Reading, after being struck down by ill health. Environmental experts hired by the former builder's insurers have advised that the 1980s property should be "out of bounds" until the risk from radiation is reduced.

One theory about the source of the plutonium – that because of the isotope levels it may have come from a nuclear reactor – suggests that its source could have been the nuclear establishment at Aldermaston, 10 miles away.

But the mystery was heightened this week when it emerged that Shell, which owned an oil depot behind Mr Fox's house, had a government licence to use radioactive material there in the 1960s.

Shell, which closed and cleaned up the site in 1988, has consistently denied that any nuclear material was stored or processed in Earley. A spokesman said: "I don't have a record of us having a licence, of having radioactive material on the site. The site was used for storing petrol and diesel. We are not sure this licence was granted to ourselves. A radioactive licence may not be used for things that may be considered as radioactive."

But inquiries by European Commission officials established that the depot was authorised to used radioactive material from 1960 to 1969. The Commission's radiation protection division has written to Mr Fox telling him the UK authorities had confirmed that the site "was granted an authorisation under the Radioactive Substances Act 1960 to use radioactive material".

It said: "This authorisation was revoked in 1969 and the radioactive material had been disposed of according to the applicable national legislation at that time."

The European Commission, having examined Mr Fox's case, has also sent a formal warning to the Government that it may not have properly implemented European law on protecting the public from environmental risks from nuclear material. The Government said that it was looking into the matter.

Experts hired by Mr Fox's insurers, who analysed the soil in his property, showed unusually high levels of man-made plutonium 239 and 240, thought to come from a nuclear installation.

In an official report written this year by Enviro Consultants and analysts for Royal Sun Alliance, the experts warned that "the property should be out of bounds until remedial action is taken to reduce the risk." The testing was carried at the former government laboratory at Teddington, Surrey.

"It is our recommendation that no one, particularly susceptible, children or young expectant mothers, should be allowed to stay at this accommodation and – based on the precautionary principle – the property should be out of bounds until remedial action is taken to reduce the risk," said the report by Dr Kartar Badsha.

Mr Fox believes the radiation could have come from a drain that ran beneath his garden. Tests on neighbouring properties found no unnaturally high levels of radiation.

Last night, Mr Fox, who has been treated in Germany for convulsions and internal bleeding, said he wanted an independent public inquiry to establish the source of the plutonium. "Basically, what they have found is there was radiation of nuclear-reactor grade in my garden. We want to know how an earth it got there. There should not be any man-made plutonium in the area.

Mr Fox said: "I have terrible pains in my leg. My feet bleed constantly day and night. What we want is honesty. I think there's been a complete cover up."

The Environment Agency confirmed yesterday that a licence to handle radioactive material was granted by the Government to Shell in 1960 but said it would not have covered plutonium or uranium. It said it would be willing to investigate if it was allowed to test the soil in Mr Fox's garden without restrictions. A spokeswoman said: "The licence would have allowed the company to use a measuring gauge which emits radioactivity. The licence does not allow anything more."