Details released under the Freedom of Information Act show the aircraft stayed on the ground for five minutes before leaving.

Dr Andrew Watt, who has raised doubts about the circumstances around Dr Kelly's death, said: "If the purpose of the helicopter flight was innocent, one has to ask why it was kept secret."

Kelly's death came soon after he was named as the source of reports questioning the Government's "dodgy" dossier arguing the case for war in Iraq.

The Hutton Inquiry found the Government weapons inspector committed suicide, but paramedics, doctors and MPs have questioned the official account of his death.