The class derives its name from the lead ship, HMS Bangor, which was launched on 19 February 1940 and commissioned on 7 November of that year.

Their lack of size gave vessels of the class poor sea handling abilities, reportedly worse even than the Flower-class corvettes.

Their shallow draught made them unstable and their short hulls tended to bury the bow when operating in a head sea.

The need for quick construction coupled with the limitations of engineering resources resulted in several variations existing based on the availability of propulsion machinery.

The class was considered cramped for the purposes it was built for, with not enough room provided for the acoustic and magnetic minesweeping gear carried.