A Christchurch family have been left with a melted conservatory roof and smoke-damaged house - but escaped with their lives after a fire, thanks to two police officers.

The pair were passing through Fair Mile at about quarter to wo this morning when they saw smoke coming from a property on Mill Road, and went in to lead the parents and two teenage children to safety.

Dorset Fire and Rescue say the incident could have been fatal, because the home didn't have working smoke alarms and internal doors had been left open.