London Bridge was the scene of another attack, on 3 June 2017, in which eight people were killed and many more injured.

This latest attack comes after the UK's terrorism threat level was downgraded on 4 November from "severe" to "substantial", 
meaning that attacks were thought to be "likely" rather than "highly likely".

The terror threat level is reviewed every six months by the Joint Terrorism Analysis Centre, which makes recommendations 
independent of government.