The UK supermarket sector is dominated by Tesco, ASDA, Morrisons, and Sainsbury's, which are the only chains which operate full scale superstores of 40,000 square feet (3,700 m²) or more. They are all fully national; there are no regional supermarket chains left in the United Kingdom which operate superstores, just a few small ones which operate smaller stores. The "Big 4" had a combined share of 74.6% of the UK grocery market in the 12 weeks to 2 January 2005 according to retail analysts TNS Superpanel.

Somerfield is the fifth largest United Kingdom food retailer, but it does not operate superstores. In February 2005, the Baugur Group, which is already the controlling minority shareholder of the Big Food Group, parent company of Iceland, made a takeover proposal for Somerfield. At least one other party has since made a counter offer.

Marks and Spencer and Waitrose are the most upmarket national supermarket chains (although the former is also the UK's largest clothing retailer, and is often not perceived as a supermarket at all). They trade from medium and small sized stores.

List of current British supermarket chains

• Aldi (German owned hard discounter )
• ASDA (owned by Wal-Mart)
• Booths
• Budgens
• Co-op
• Costco (this is a warehouse club and predominantly a wholesaler, but 30% of UK sales are to individuals.)
• Costcutter (a symbol group and really a convenience store)
• Farmfoods (a frozen food specialist}
• Iceland (indirectly controlled by Baugur Group of Iceland (sic)).
• Kwik Save (owned by Somerfield)
• Lidl (German owned hard discounter )
• Londis (a symbol group and really a convenience store)
• Marks and Spencer (also the UK's largest clothing retailer)
• Morrisons
• Netto (a Danish owned hard discounter )
• Sainsbury's
• Somerfield
• SPAR (a symbol group)
• Tesco
• Waitrose (owned by the John Lewis department store chain)

• Alldays, Day & Nite, Local Plus, and Safeway are being rebranded following their take overs.

List of defunct British supermarket chains

• AllDays (bought by Co-op)
• Bejam (bought by Iceland)
• Day & Nite (bought by Tesco)
• Fine Fare (now Somerfield)
• Gateway (Now known as Somerfield)
• Local Plus (bought by Co-op)
• Presto (supermarket) (regional?)
• Safeway (UK) (bought by Wm Morrison)
• Wm Low (regional in Scotland and northern England)

(Safeway Compact Stores sold on to Somerfield)

See also

For supermarkets worldwide see List of supermarkets.