The M&S Foodhall has created 60 new jobs.
It opens as the town’s existing High Street store celebrates its 80th anniversary.
The 9000 sq. ft foodhall, which has taken over the unit previously occupied by JJB Sports, features 5000 product lines, an in-store bakery and Coffee to Go cafe.
A ribbon cutting ceremony will take place at 10am.
Normal opening hours will be Monday-Wednesday and Saturday from 8am to 8pm, Thursday and Friday from 8am to 9pm and 10am to 6pm on Sunday.