Currys PC World and AO.com have attacked a Which? report raising questions marks over their Black Friday deals.

The consumer rights group said it believed both retailers could be breaking government guidelines over their discounting strategies.

Which? highlighted that when promoting a discount like ‘was £100, now £50’, the ‘was’ price should be the most recent price the item was sold at for 28 consecutive days or more, and “not a price that is more than six months old”.

However, Which? said it had found examples at Currys PC World, owned by Dixons Carphone, and AO.com “where this had not been done”.

A Currys PC World spokesperson said: “We are proud to offer our customers fantastic deals all year round, with prices that are truly transparent and backed by our Price Promise.

“We fundamentally disagree with the approach taken by Which? in this report and comply fully with the PPG guidelines”

Currys PC World

“We fundamentally disagree with the approach taken by Which? in this report and comply fully with the Pricing Practices Guide guidelines, displaying a clear date from when the ‘was’ price was taken, allowing customers to make a fully informed decision.”

In a statement AO.com said: “We offer the most comprehensive and clear price match guarantee to our customers and are continually changing prices to ensure we offer the best price in the electricals market and that customers get the best value for their money.”

The Which? investigation tracked deals on tech gadgets and home appliances on Amazon, AO, Argos, Currys and John Lewis in the three months before and two months after Black Friday last year.

The group found half of products “on offer” during Black Friday last year were cheaper before or after November 27.

Amazon has already launched its Black Friday offers for this year, while Argos begins a 13-day spectacular from Friday.

Shoppers are predicted to spend £6.77bn online in Black Friday week, according to data from IMRG and SimilarWeb.