The women, named locally as Sue Barker and Ann Ryan, were killed in the blast in the small building in Immingham, North East Lincolnshire.

Mrs Barker's husband Tony was seriously injured in the blast, which left the business he ran on a garage forecourt, Fred's Taxis, just a blackened shell.

Firefighters investigating the explosion and fire at the premises on Pelham Road said they believe the incident was a "terrible accident".

Some local people said they believe Mr Barker, who has run the business for many years, may have entered the small office with a petrol can which for some reason exploded.

Mr and Mrs Barker's semi-detached house, which is about a mile from the scene of the blaze, was empty. The Christmas lights in the windows were turned off.

A woman, believed to one of their three daughters, arrived later but did not want to speak about what happened. The couple are believed to have been in their 40s.

Neighbours said they had lived in the house for about five years.

At the scene, the burnt-out taxi office could clearly be seen from the road as fire investigators and police forensic teams combed the area outside.

The small office was completely destroyed in the explosion and fire, with both windows and the door blown out.