CRIMES related to alcohol have increased by more than 50% on Scotrail trains since a drink ban was introduced on its services last summer.

Transport police have been called to deal with 15 violent assaults and two sex offences in the six-month period after passengers were barred from drinking.

Figures released by British Transport Police (BTP) under freedom of information legislation revealed it recorded 71 alcohol-related crimes between November 1, 2012 and April 30, 2013 – after the ban came into force – compared to 46 during the same six-month period a year earlier, an increase of 54%.

Over the same period, the number of incidents BTP officers dealt with on Scotrail trains – not necessarily incidents involving alcohol – increased 6%, from 5278 in 2011/12 to 5604 in 2012/13.

It comes despite expectations that banning alcohol would help to curb antisocial behaviour.

Scotrail is responsible for 95% of train services in Scotland, running 2000 routes a day. It launched its ban in July last year, with the sale and consumption of alcohol on board forbidden between 9pm and 10am. Drunk passengers were also be stopped from boarding.

However, the figures provided by BTP show that violent drink-related assaults increased, from 10 in November 2011-April 2012 to 15 in November 2012-April 2013. Police also recorded two sexual offences in the six months after the ban compared to none beforehand, while minor public order offences increased from 32 to 50.

A spokesman for the Rail Maritime and Transport (RMT) union, which represents train workers, described the figures as alarming.

He added: "If it's increased we would want to know why. We are always concerned about assaults on our staff, so if there has been an increase we would want to discuss that with the employer. Often these incidents are linked to football or concert-goers, as well as people coming off ferries with Duty Free."

In the six months running up to the ban being introduced in July last year it was reported transport police had dealt with around 260 alcohol-related incidents.

However, in the FOI response the BTP said it would be too expensive to give a breakdown on how many of the "incidents" their officers responded to on ScotRail trains involved alcohol.

The number of "alcohol-related crimes" given refer to cases where the officers' log suggested an offence had taken place.

Mike Hewitson, head of policy at the independent watchdog Passenger Focus, which campaigns on behalf of rail users, said: "Passengers tell us that having more people patrolling the train makes them feel safer and that is to be welcomed.

"Although some of these figures could be explained by greater reporting, it is worrying to see any increase in behaviour that makes passengers feel threatened. As awareness of the ban grows we'd hope to see behaviour changing and these numbers decreasing."

Chief Superintendent Ellie Bird, area commander for the Scotland for BTP said: "During the period April 2011 to March 2012 the Scotland area successfully achieved an objective to detect offenders indulging in anti-social behaviour.

"Officers will continue to support ScotRail in its efforts to combat alcohol-fuelled anti-social behaviour at stations, as it is recognised excessive alcohol consumption can be a contributory factor to the issue on the rail network."

ScotRail managers believe increased awareness may account for the increase in reports to BTP.

A spokeswoman for ScotRail said: "We are encouraged to see the number of accidents at stations has decreased by around 16% since the ban was introduced.

"We have always recognised it will take time to change ingrained behaviours, and we remain committed to our long-term objectives to ensure customers can travel in a pleasant environment."

East Coast also recently implemented a zero-alcohol policy on its Friday morning service from Aberdeen to Newcastle after a spate of incidents involving inebriated passengers on the route, which is popular with hen and stag parties.