Social housing providers are enlisting satellite and internet tracking technology in the fight against drugs, crime and antisocial behaviour.
Bristol's Knightstone Housing Association, caught on the front line of a running battle between drug gangs, is one of around 25 registered social landlords and council housing departments using modified mobile phones to protect staff.

Housing officers and neighbourhood wardens share six phones fitted with GPS technology.

The phones signal their location to a base station. Colleagues can use a website to follow their progress on a map.

Staff caught in a dangerous situation can press an emergency button on their phones allowing security consultants to listen in and record the conversation for future evidence or call the police to the location.

The system, supplied by security company Orbis Monitoring Service, is used by around 150 public sector companies.