People wait outside a Currys PC World shop before the early opening of the Black Friday sales on Tottenham Court Road in London, November 27, 2015. [Photo/Agencies]

LONDON - Britons chased "Black Friday" shopping bargains on Friday with initial signs that many were going online rather than heading to stores for an event imported from the United States.

Retailers are hoping the promotions will kick-start Christmas trading after a weak November when, according to an industry survey published this week, sales grew at the slowest rate in nine months.

Retail researcher Conlumino is forecasting the event will generate UK sales, both in stores and online, of 1.6 billion pounds ($2.4 billion), up 20 percent on 2014.

"It looks as if Black Friday spending has been more spread out this year and more weighted to online, but every indication is that the combined event will be bigger than last year," said independent retail analyst Nick Bubb.

In the United States, Black Friday, the day after the Thanksgiving holiday, was so named because spending would pick up and retailers would begin to turn a profit for the year and move into the black.

Introduced into Britain in 2010 by U.S. online retailer Amazon, the day has become an important part of the shopping calendar as more and more chains join in.

However, last year's event caused long queues and sparked brawls in stores as shoppers fought over bargains. That may have encouraged more people to shop online this year.

British retailers are anxious to avoid a repeat of last year's trading pattern when the surge in low-margin sales was followed by weaker-than-expected demand, as shoppers held back in the hope of further discounts.