Rail workers in Sussex may be asked to carry DNA testing kits to combat spitting assaults.

Staff would bottle samples and begin testing the spit to identify offenders.

Inspector Gary Ancell, of British Transport Police at Brighton station, said: "Spitting is a problem for staff and is utterly objectionable. There are few things worse than having spit in your face."

Rail staff are already asked to try to keep spit for DNA testing but plans are now in the pipeline to issue them with testing kits.

Pilot projects are already under way in Birmingham. Mr Ancell said: "It is something we are considering for this area.

"Once we have got a spit sample and an offender's DNA it can be checked with the national DNA database in Birmingham. The offenders will then get a visit from us."

Mr Ancell said train staff endured a number of incidents of spitting and of verbal threats against them every month, more than incidents of physical assault.

Sussex Police, meanwhile, are closely watching a scheme to issue football-style "yellow card" warnings to yobs.

The Surrey force no longer tolerates loutish behaviour and slaps offenders with the warnings. Repeat offenders are arrested.

A spokesman for Sussex Police said: "We are watching the progress of the scheme but we have no plans at present to introduce anything similar."