SCOTRAIL will deploy extra staff at key stations tonight as it implements the UK's first blanket alcohol ban on late night services.

The operator said it would take a softly softly approach in the first fortnight as passengers got used to the ban. It will affect all trains and stations from 9pm to 10am, bar the Caledonian Sleeper. The firm says bag searches and other heavy-handed tactics will be avoided.

The crackdown, aimed at tackling anti-social behaviour, has been welcomed by Scottish Government ministers but provoked a cautious response from rail watchdog Passenger Focus, which warned it could prove unenforceable and see thousands of people targeted who are not causing any problems.

As well as banning consumption of alcohol, ScotRail and British Transport Police (BTP) have promised a tougher approach in preventing intoxicated passengers from boarding trains.

BTP said it would have a high-profile presence tonight to support ScotRail staff. Steve Montgomery, ScotRail's managing director, and BTP's area commander for Scotland, Chief Superintendent Ellie Bird, are expected to be out with rail staff and police officers tonight when the ban comes into force.

However, it is not expected to lead to an increase in arrests initially. "The first two weeks will very much be about education and awareness," a spokesman for the force said.