Retailers are getting ready for another record Black Friday despite days of sales ahead of the event and warnings to consumers to spend sensibly.

The global sales bonanza – originally a 24-hour affair – now comes after two weeks of intense efforts by retailers who still expect to set another record for sales tomorrow.

Retailers are promising a fresh set of deals online from midnight, and a number of chains are extending their opening hours.

Some John Lewis stores will open later, a “few” Argos outlets are opening early and 187 Tesco Extra stores are closing at 1am and reopening at 5am on Black Friday.

Tesco said last year’s Black Friday, which lasted a week, saw more than six million visits to the Tesco Direct website – a 40 per cent increase on traffic.

Argos enjoyed record sales last year and John Lewis had its biggest week of sales in 153 years.

However, analysts point to the event moving increasingly online and expect high street figures to be up just four per cent on last year, with scenes of brawls over cut-price TVs unlikely to be repeated.

Britons are expected to spend £2.6 billion tomorrow alone – an eight per cent increase on last year. Institute of Customer Service’s chief, Jo Causon, said: “Retailers should not view Black Friday simply as an opportunity to shift discounted stock. They must uphold a responsibility to ensure customers receive a high quality experience too.”