He told BBC Radio 4's Today programme that it depends on a number of factors including:
- How the body has been buried
- What condition it was in when it entered the ground
- How expensive the coffin was
- Whether modern embalming techniques were used
He said: "I think it is certainly possible that they could find residual traces of radioactive material," but added it was doubtful they would find solid evidence of poisoning if only bones remain.
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A widespread frost across the UK as temperatures fall below freezing under clear skies.
After a vote tainted by reports of ballot-box stuffing and forced voting, Putin said Russia was ready to 'cooperate' with Britain.
Largely dry elsewhere tonight with a widespread frost and icy stretches