Sir Nick Clegg has jumped to Facebook’s defence on the issue of hate speech as Lego joined the growing list of global firms to halt advertising on the platform.

The social network has been hit by a widening boycott after it refused to take down a post by Donald Trump.

During Black Lives Matter protests in the wake of George Floyd’s killing, the US president said: “When the looting starts, the shooting starts.”

In an open letter, former Liberal Democrat leader Sir Nick said the tech giant understands many critics are angry about the president’s “inflammatory rhetoric”.

“When content falls short of being classified as hate speech — or of our other policies aimed at preventing harm or voter suppression — we err on the side of free expression because, ultimately, the best way to counter hurtful, divisive, offensive speech, is more speech,” he said.

“With so much content posted every day, rooting out the hate is like looking for a needle in a haystack.”

Hundreds of companies have responded to the #StopHateforProfit campaign by pausing adverts on the platform for either the whole of July or the rest of the year, while others are reassessing use across all social media sites.

Big names including Coca-Cola, Adidas and Unilever are among the list.

Several reports claim that Facebook executives have held crisis talks with marketing and advertising agencies in a bid to ease concerns.

Facebook says it has spent billions of dollars each year in people and technology to keep the platform safe, tripling its safety and security workforce to more than 35,000.

Sir Nick – who joined Facebook as its head of communications in 2018 – announced that on Friday every Facebook user of voting age in the US will be given information displayed on the top of their News Feed on how to register to vote, arguing that “the only way to hold the powerful to account is ultimately through the ballot box”.

“I want to be unambiguous: Facebook does not profit from hate,” he explained.

“We may never be able to prevent hate from appearing on Facebook entirely, but we are getting better at stopping it all the time.”