Robbery, drug offences and criminal damage have all gone up on the Tramlink network.

But sexual offences, serious public disorder and theft of passenger property have all dropped.

The latest figures from Transport for London show a mixed picture for the quarter July to September 2011 compared to the corresponding period last year.

Robbery saw a 600 per cent increase from two offences in 2010 to 14 in 2011, with drug offences rising from 9 to 14 and criminal damage up from 12 to 16.

But there were no sexual offences on the network, which serves Croydon and Wimbledon, compared to one last year, while theft of passenger property halved from 10 to 5 and serious public disorder dropped by a third from 21 to 14.

Figures have also been released showing a drop in bus-related crime in Croydon in the same period.

Offences have dropped by just over 10 per cent since last year from 205 to 184.