POLICE investigating the deaths of two boys on a railway line have pledged to take tough action against anyone caught selling alcohol to children.

One line of inquiry into the deaths of Stuart Adams, 15, and Lee Mullis, 14, is that they had been drinking before the accident, on the East Coast Main Line at Darlington.

Detectives said they could not confirm that alcohol played any part in the deaths, and would not comment until they received laboratory reports.

But they pledged a crackdown on underage drinking if a link was shown.

Friends who were with the teenagers on Friday night, only minutes before they were hit by the 8.30pm Manchester Airport to Newcastle service, said the group had been drinking.

The boys were killed instantly as they played on the track near the Five Arches bridge.

Last night, tributes from across the town were paid to the two sports-mad youngsters.

Lee and Stuart excelled at sport, and played in the same Darlington 21st Allstars football team.

Lee was also a talented golfer, and was due to represent Durham in an inter-county competition on Thursday.

He had also been selected to take part in a coaching course with some of the best young players in England.

Acting Inspector Alison Jackson, of Durham Police, said a Streetsafe unit had recently been created in Darlington to target a hard core of youngsters who cause trouble across the town, and to tackle the problems of alcohol and anti-social behaviour.

Acting Insp Jackson said: "We are not sure if the two youths had been drinking, and will not be until we get the results of the toxicology tests.

"We will also be speaking to witnesses about the night's events. We are dealing with it in the appropriate way, and will not speculate.

"However, if it comes to light that drink did play a part, then it will become a main priority.

"If alcohol has been a contributing factor, then it is something we will be looking at, and we will be stepping up our actions and trying to make sure that something like this does not happen again.

"Underage drinking has always been a concern, and these events have really brought it to the forefront."

Acting Insp Jackson said that underage drinking was a difficult problem to tackle, but was pleased with the progress the Streetsafe team had made.

"The unit has done a really good job, even though it is in its infancy, and has done a lot to target anti-social behaviour at its source.

"Tackling alcohol is already a central part of dealing with anti-social behaviour, and the creation of Streetsafe shows how committed we are to it.

"Drinking is a difficult thing to combat, but we want to make sure nothing like these terrible events happens again.

"We are determined to continue our efforts to stop kids getting hold of alcohol, and prosecuting the people who get it for them."