The letter told athletes that “following a significant security incident overnight,” they must follow a number of protocols, including not wearing Team GB kit out of the village and not taking taxis, for their own safety.
The letter, which has been seen by the Guardian, also warns athletes they must “avoid leaving the village after dark in anything other than British Olympic Association/Local Organising Committee/UK Athletics transport – taxis cannot be considered safe late at night. If you are planning on going out after dark and have no way of returning other than via taxi, do not go out.”
It also tells them of the dangers of going out on the town, and tells them they must inform officials before they go out.