Gordon Brown is being urged to intervene in an investigation into the mysterious death of British scientist Timothy Hampton. The nuclear expert fell to his death from the 17th floor of a UN building in Vienna last month.

Local police and UN officials have suggested that the 47-year-old, who was involved in monitoring illegal nuclear tests by Iran and North Korea, killed himself.

But tests commissioned by his family have raised doubts about the findings of a first post-mortem examination and suggest that Mr Hampton, from Newbury, may have been murdered.

One theory is the scientist could have been strangled, carried from his workplace on the sixth floor and thrown to his death. Richard Benyon, Mr Hampton’s MP, said: ‘I have grave misgivings about this case. I am told Mr Hampton was not suicidal.

‘He was happy in his work, loved living in Vienna and was devoted to his partner and three-year-old child…