The North Norfolk MP Duncan Baker says he is devastated at the loss of the Budgens shop he worked for and run by the Baker family.
The independently-run supermarket is the only one in Holt and also houses the town's post office.
Mr Baker said he was horrified by the fire and would do all he could to support the family and the local community.
Fire crews are expected to be at the scene in Kerridge Way for most of the day.
C T Baker Ltd is an historic company formed in 1900 but with much earlier roots.
It's just marked its 250th year of trading. The original shop in the Market Place has served the town as a shop since 1730 or thereabouts, with the involvement of the Baker family beginning in the 1760’s or 1770’s.
The company runs the Larners shop in the Market Place and a number of builders merchants across North Norfolk.
In 2007 the supermarket of Budgens was added to the Group offering local products from local suppliers to local people. The company also runs a Budgens in the nearby town of Aylsham.
The CT Baker group employs over 250 staff within the three divisions of Department Store retailing, Builders Merchants and Budgens supermarket.