It is hoped the kits issued to staff will help to identify offenders

Strathclyde Partnership for Transport (SPT) has invested in 300 swab kits which enable staff who have been spat at to take samples of the saliva.

Samples can be passed on to police who will check them against a DNA database which could identify the offender.

SPT said spitting incidents were rare but did occur on the underground.

Ron Hamilton, customer and commercial officer for the subway, said: "By issuing these kits to our staff, we hope those who behave in such an unacceptable manner will think twice about it when they realise we now have the means to catch them."

"Knowing these kits have proved to be a successful deterrent for other public transport operators, we decided to do the same as we are keen to reinforce to the minority of passengers, who engage in this type of action, that we will not tolerate such behaviour.