A building dating back to the 1850’s in downtown London was heavily damaged by a suspicious fire early Monday morning.

The building which currently houses law offices was once part of Banker’s Row as part of the original commercial area of London.

The fire broke out just before 5 a.m. at 435 Ridout Street at the corner of Queen Street.

Damages to the inside is extensive. While a damage estimate has not been released, officials expect the number to be high.

The cause of the fire is under investigation.

The Ontario Fire Marshal has been called in to help with the investigation.