A thief broke into the Tower of London, the castle where crown jewels are kept.

The thief managed to scale the front gate and steal the bunch of keys from a special metal box, the Sun reported quoting its source.

The Tower guards – famous Beefeaters – saw the thief but did not move as they do not have to leave their post under strict rules.

The locks had been changed but the incident raised questions on the level of security in the Tower, The Daily Mail reported.