Nike sales surged by 31 percent following the controversial campaign fronted by Colin Kaepernick.

A report from Edison Trends, a top advertising research firm, found that sales in the sports retailer increased by almost a third compared to the same period last year.

The decision for Kaepernick to be the face of the campaign was a controversial one after in 2016 he refused to stand for the national anthem in protest at police brutality and racism.

“There was speculation that the Nike/Kaepernick campaign would lead to a drop in sales, but our data over the last week does not support that theory,” said Edison Trends co-founder, Hetal Pandya.

Following the announcement of the advertising campaign, people released images of them burning Nike materials onto social media.

Donald Trump has also voiced his anger at Nike’s choice of sports star for the recent campaign.

“Nike is getting absolutely killed with anger and boycotts,” Trump said.”I wonder if they had any idea that it would be this way?”

“As far as the NFL is concerned, I just find it hard to watch, and always will, until they stand for the FLAG!”

Nike have defended the deal and said Kaepernick was “one of the most inspirational athletes of this generation”.

Serena Williams, who is also part of the campaign, praised the decision. Williams said the retailer’s decision to use Kaepernick a “powerful statement to a lot of other companies”.

Shares in the group (NYSE: NKE) are up 2.15 percent at 82,03 (1631GMT).