LONDON (REUTERS) - Three men appeared in court on Thursday charged with terrorism offences relating to an alleged plot to carry out a beheading in Britain.

The men were arrested in London and High Wycombe, west of the British capital, two weeks ago.

Nadir Ali Sayed, 21, his cousin Yousaf Shah Syed, 19, and Haseeb Hamayoon, 27, were charged with preparing to commit acts of terrorism.

Prosecutors said the charge related to a plot to behead a member of the public.

The men were remanded in custody to appear at London's Old Bailey court on Dec 4.

British police have made a series of arrests in recent months since the country's international terrorism threat level was raised to the second-highest rating of "severe," meaning an attack is considered highly likely.

Prime Minister David Cameron has also warned that Islamic State militants who have seized swathes of territory in Syria and Iraq, pose a serious threat to Britain's national security.