Firefighters yesterday said a chimney fire was the most likely cause of a major blaze which tore through a row of historic thatched cottages in a Devon town at lunchtime on Thursday, leaving families homeless.

Crews remained damping down at the scene of the blaze in Crediton, near Exeter, all night and into Friday morning, hours after it engulfed six properties in Buller Square, on Mill Street.

At its height, 100 firefighters from across Devon battled the inferno as it took hold in the thatched roofs of five cottages, which are thought to date back more than 500 years, then spread to a sixth property.

The historic part of Crediton – feted as the traditional birthplace of St Boniface – was sealed off to traffic as fire crews in 25 appliances arrived to quell the blaze.

Neighbours could only look on in disbelief at a pillar of smoke visible as far away as Exeter, as the fire rampaged through one of the most photographed parts of the town.

Nobody was injured in the fire, and all residents were out of the properties by the time the emergency services arrived. But some were understood to be concerned about the welfare of their pets, which they had been unable to return to save.

Six relief crews remained at the scene all night to ensure the fire was properly damped down, with two crews still remaining on Friday morning.

Crediton deputy mayor Joyce Harris, who lives near the scene, described the fire as "absolutely devastating" and said the town was very concerned for those left without homes.

She said: "The roads were closed off and there were police and fire crews everywhere. The whole town is very worried about it because several families will be affected.

"It's also a historic part of Crediton – the buildings are very old and it's near the birthplace of St Boniface."

Mid Devon Council said the homeless families were thought to be staying with families and friends.

The incident caused tailbacks and traffic congestion between the East Street junction and the A377 Exeter Road junction.

A spokesman for Devon and Somerset Fire and Rescue Service said: "The incident is believed to have been started by a chimney fire."

Some residents took refuge in the St Boniface Centre, attached to Crediton Church. The rector, the Rev Nigel Guthrie, said many had already been taken in by friends or relatives, but said the church would work to provide food, clothing and accommodation for those who had not.