The diplomat - one of five UK Government officials and an American detained in the capital Kinshasa - was told to leave the country on Wednesday.

A Foreign Office spokesman said: "A member of embassy staff has been asked to leave Kinshasa by the authorities. He is making arrangements to leave the country."

The FO declined to discuss any personal details of the expelled worker but confirmed he was not the British ambassador to the central African state.

The UK Government earlier demanded the "immediate release" of the four and an American, detained in the Democratic Republic of Congo.

The men have been under house arrest at their hotel in the capital Kinshasa since Sunday after allegedly being found with marked maps of the city by Congolese troops.

Protection team

The Foreign Office in London denies Congolese reports that the officials were spying.

Foreign Office minister Tony Lloyd telephoned President Laurent Kabila on Tuesday night to say that the UK was treating the matter very seriously.

A Foreign Office spokesman said the officials were in Congo to review contingency plans in the event of an emergency.

Two of the Britons are from the Ministry of Defence, one from the Foreign Office and the other is a member of the British Ambassador's protection team in Kinshasa. The American was on a secondment from the State Department to the Foreign Office.

The British Ambassador in Kinshasa, Douglas Scrafton, is trying to resolve the matter with the Congolese Government.

Suspicions of spying

Kinshasa newspapers reported that the men were arrested with maps near a military airfield on suspicion of spying.

Congolese Government forces are currently involved in a conflict with rebel troops seeking to overthrow President Kabila.

Last August, rebels came close to entering Kinshasa before being beaten back by government soldiers supported by troops from Zimbabwe and Angola.

Correspondents say the Congo authorities have accused the rebels of hiring foreign mercenaries and suspicions of foreigners have heightened in recent weeks.