The National Police Chiefs' Council (NPCC) has warned retailers to be prepared with adequate security on Black Friday, after scuffles broke out among bargain-seeking shoppers during last year's event.
Black Friday, introduced to the UK five years ago, is regarded as the beginning of the Christmas shopping season in the United States, when major retailers open early and offer shoppers hugely discounted prices.
Black Friday has become the biggest shopping day of the year, and the Centre for Retail Research estimates that total Black Friday sales in the UK (in-store and online) will reach £1.39bn, while shopping over the entire weekend will approach £3.5bn.
Police were called to at least four overcrowded supermarkets in London at last year's event, as shoppers trampled over each other and fought over promotional goods. Several arrests were made and stores were forced to close due to the scuffles.
Deputy chief constable Sue Fish, of the NPCC's Business and Retail Crime unit, has warned shops that the sales should be appropriately staffed, and stores need to provide adequate in-store security to prevent a repeat of chaotic scenes from last year's event.
"The police will intervene if necessary to protect public order and safety," Fish said.
"But we should be the service of last resort, not a substitute for carefully-considered in-store security plans.
"Having to deploy officers to deal with the fallout of highly-marketed but under-staffed sales in shops diverts valuable resources from other areas of policing and is in most cases avoidable through advance planning."
The Black Friday sales are due to take place on 27 November.