British police on Thursday charged four people with terrorism offences following their arrest in operations carried out earlier this month.

Metropolitan Police charged three men from London with preparing for acts of terrorism and one woman with possession of a document likely to be of use to a terrorist.

All four will appear at London's Westminster Magistrates' Court later Thursday.

The three men were named as Richard Dart, 29, Imran Mahmood, 21, and Jahangir Alom, 26. The woman was identified as 22-year-old Ruksana Begum.

The three men are accused of travelling to Pakistan for training in terrorism and travelling abroad to commit acts of terrorism.

With the Olympic Games due to start in London on July 27, Britain's security threat level is currently set at "substantial", meaning officials believe there is a strong possibility of a terror attack.

The threat level was reduced from "severe", meaning an attack is highly likely, in July 2011.