The new Co-op store at the Elephant & Castle Shopping Centre opened its doors to customers on Saturday morning.
Bermondsey & Old Southwark MP Neil Coyle cut the ribbon to declare the store open.
The Co-op occupies the front portion of the former Tesco Metro store which closed its doors six months ago amid reports of a rodent problem.
"We are excited about the opening of the new Co-op store," said Diana Barranco, community director for the centre's owners.
"It is important that the shopping centre continues to be a vibrant shopping destination for the local community.
"We hope the opening of Co-op will help towards boosting footfall and supporting trade in the centre."
The new Co-op is open Monday-Saturday 7am-10pm and Sunday 11am-5pm.
Later this autumn the High Court will consider an application for judicial review of Southwark Council's decision to approve the demolition and redevelopment of the shopping centre.
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