Firefighters did not finish putting out the last flames until 24 hours after a fire started.

It was still burning in an inaccessible part of a wall between the Lloyds TSB offices and a disused casino in Queens Road, Brighton, yesterday despite crews working throughout the night to quench the flames.

The busy city centre road was closed until 12.30pm yesterday while crews from Brighton's Preston Circus fire station removed corrugated iron from the casino roof to get to the fire which started on Wednesday afternoon in a 13in cavity wall between the two buildings.

Queen's Road was closed for a further 45 minutes yesterday afternoon while a final check was carried out before structural engineers assess the damage today.

The fire is believed to have started accidentally. Smoke billowed into the neighbouring buildings, affecting five floors of the Lloyds TSB offices.

Ninety staff, who were evacuated and sent home for the day, will not return to the building until Monday at the earliest. The staff, who work in the company's IT and operations departments, have been working from home and other offices.

A company spokeswoman said she would not know the extent of the damage until after the engineer's report. She said: "If it's just smoke damage then it will just be a cleanup job but if the damage is more serious it could take longer."

Grant Eager, of Preston Circus fire station, said: "The buildings have been scorched by the flames and heat but the fire doesn't appear to have spread."