The UK’s competition watchdog is set to take mattress seller Emma to court over its online discounting, which it said could be misleading shoppers.

The Competition and Markets Authority (CMA) started investigating the retailer two years ago.

The watchdog had concerns over Emma’s sales practices such as “countdown timers” and high demand prompts, which it found could mislead shoppers.

Countdown timers are a tool used by retailers to create a sense of urgency among shoppers, by encouraging them to make a purchase before the clock on a deal runs out.

The CMA’s probe also found that Emma’s website showed extensive discount offers, but there was evidence that only a small fraction of its products were actually sold at full price.

Emma was asked to make changes to its so-called “reference pricing”, which are used by retailers to show if a product was previously sold at a higher price.

But the CMA said on Friday that the retailer, which is one of the UK’s best-selling mattress brands, failed to take the necessary action to address all of its concerns.

A spokeswoman for Emma said it has made “most of the adjustments the CMA asked for” including changing how it used countdowns and ending other urgency tactics.

She added: “However, the CMA wants Emma UK to also limit the number of products sold at a discount off the full or ‘reference’ price.

“Specifically, the CMA wants us to limit the quantities that can be sold at a headline discount to twice the amount of the product sold at the undiscounted price.

“We believe implementing such a requirement would deprive consumers across the UK of the best and most popular deals, as promotions may have to end early.

“This unnecessary red tape will harm consumers in the UK.”

Emma said it had therefore decided not to settle with the CMA on its requirements to change the pricing tactic, and stressed it was “now in full compliance with consumer law”.

The watchdog, which currently does not have the power in its own right to fine a company for breaching consumer law, said it had launched legal action on Friday.

George Lusty, the regulator’s interim executive director for consumer protection and markets, said: “We have given Emma sufficient opportunity to alter the way it does business to address our concerns.

“They have failed to make all the changes that we require, which is why we’ve progressed to court action.

“We are concerned that when sales tactics such as discounts and countdown clocks are used in a misleading way, they can pressure shoppers into making quick purchases and spending more than they otherwise would, for fear of missing out.”

Emma can still agree to make changes by consenting to an order or giving commitments to the court before the case is heard, the CMA said.

A date for the hearing will be determined by the court, which will then decide whether or not Emma has breached consumer protection law.

Rocio Concha, Which? director of policy and advocacy, said: “We support the CMA in taking legal action to protect consumers from unfair sales and marketing practices and we are disappointed that Emma Sleep has not fully complied with the regulator’s requirements to date.

“We are suspending Emma Sleep’s Which? best buy endorsements pending the outcome of this court action.”