Co-operative Group is to invest£20 million revamping 160 Alldays stores this year as the integration of the 600-strong c-store chain gets under way.
The shops are to be rebranded Co-op Welcome and will carry a strengthened fresh and chilled food range.
Co-op acquired Alldays last October in a£131 million deal. Since then, executives from both businesses have been working on an integration plan, which is now being implemented.
Co-operative Group retail controller Malcolm Hepworth said the integration comprises nearly 90 separate projects, taking in areas such as systems, ranging and supply chain.
The consultation process with Alldays' head office staff at Eastleigh in Hampshire has finished, with 150 leaving the business. However, the Co-op will retain the property as a regional office. The Co-op's Manchester office will continue as headquarters for the merged operations.
Hepworth said: 'We have used people (on the integration) who have experience from working on the merger with CRS. We are to convert 160 stores by the end of the this year, and then 200 a year after that, so we'll have the lot done within three years.'
Hepworth added that the 10 Alldays outlets that were converted to Co-op stores at the start of the year have performed well, achieving sales increases of approximately 30 per cent.