Black Friday deals will appear on retailers' websites from midnight but some are opening stores earlier than usual.

Here is a list of major retailers' earliest opening times, but customers are advised to check online for details about their local branches.

Boots: three stores - Liverpool Street Station, Piccadilly Circus and the flagship Oxford Street branch will open at 12.30am. All other stores will open as usual.

Tesco: Tesco stores involved in Black Friday, which will all be larger Extra branches, will open at 5am. Each store has been individually assessed to ensure there are enough security guards and barriers or queuing systems in place, and stock volumes have been increased to help meet customer demand.

Sainsbury's: Four 24-hour stores - Lincoln, London Colney, Harringay and Bybrook - will close at midnight and reopen at 6am. There are no other changes to regular opening hours.

Argos: 688 Argos stores will open at 6am.

Currys PC World: A selection of stores will open at 6am. Customers are advised to check online for local store opening hours.

John Lewis: Shops will open early at 8am. Queuing systems will be in place across both shops and online to ensure that customers have a good shopping experience.

Debenhams: Store times vary but many will be opening an hour early at 8am and stay open later until 10pm. The flagship store on Oxford Street will stay open until 11pm.

Marks & Spencer: No change to usual opening hours.