Police have warned of a dangerous new trend which sees passengers hanging out of windows on trains.

British Transport Police (BTP) announced officers will be conducting patrols on Greater Anglia trains in Norfolk and Suffolk today.

BTP warned passengers that the risky stunt is also against the law and offenders risk prosecution.

In a post on the BTP East Anglia Twitter account it said: "BTP officers will be conducting patrols on the class 37 loco due to a new extremely dangerous trend of passengers hanging out of the carriage windows.

"Not only is this exceptionally dangerous, it is also illegal under the byelaws and offenders will be prosecuted @greateranglia".