Downing Street on Monday strongly rejected Labour claims that Boris Johnson had given cover to racists who targeted online abuse at members of the England team following their Euro 2020 final defeat against Italy.

England manager Gareth Southgate condemned the racist social media attacks as “unforgivable”, but in the raw aftermath of the Wembley final a political row broke out over Johnson’s handling of race and cultural issues.

At the start of the tournament Johnson declined to condemn fans who booed England players “taking the knee”, the anti-racism gesture, while home secretary Priti Patel said fans had a right to boo.

Following England’s defeat in a tense penalty shoot-out, racists singled out Marcus Rashford, Jadon Sancho and Bukayo Saka on social media for missing their penalty kicks.

Johnson condemned the “appalling” social media abuse aimed at black players following the match, calling the team “heroes”. Meanwhile, Patel said she was “disgusted” by the “vile racist abuse”.

But Angela Rayner, deputy Labour leader, wrote on Twitter: “Boris Johnson and Priti Patel are like arsonists complaining about a fire they poured petrol on. Total hypocrites.” Sir Keir Starmer, Labour leader, said Johnson had “failed the test of leadership”.

On Monday evening, one black member of the England squad, Tyrone Mings, attacked the home secretary directly on social media over her role.

He retweeted Patel’s condemnation of the abuse and wrote above it: “You don’t get to stoke the fire at the beginning of the tournament by labelling our anti-racism message as ‘Gesture Politics’ and then pretend to be disgusted when the very thing we’re campaigning against happens.”

And in an emotional message to fans, Rashford tweeted that he expected to be written about, whether for the colour of his skin, where he was from or his off-pitch behaviour.

“I can take critique of my performance all day long . . . but I will never apologise for who I am and where I came from.”

Meanwhile, former England player Gary Neville said: “The prime minister said it was OK for the population of this country to boo those players who were trying to promote equality and defend against racism. It starts at the very top.”

Downing Street denied that claim, saying Johnson had been making the point he “wanted to see people cheering the team, not booing”. Johnson tweeted on Monday that the people abusing England players “should be ashamed of themselves”.

Earlier Southgate condemned the online abuse, adding that his team had “been a beacon of light in bringing people together in people being able to relate to the national team, and the national team stands for everybody and so that togetherness has to continue”.

He added: “For some of them to be abused is unforgivable really. It’s just not what we stand for.”

Prince William said he was “sickened” by the racism.

The incidents show how social media companies have struggled to crack down on racism and abuse on their platforms, despite high-profile players, including the England team, and lawmakers repeatedly calling for action.

Footballers are often lambasted on social media after losing a match but the worst abuse is typically reserved for black footballers and ethnic minorities. English football, including the Premier League and its clubs, boycotted Facebook, Twitter and Instagram in April to draw attention to the abuse.

England players have continued to take the knee before matches but a minority of fans have booed.

The racism will also add to security concerns, questions about the policing of the event and how fans conducted themselves throughout the day.

The Football Association, the sport’s domestic governing body, said it would support the players and pursue the “toughest punishments” for those responsible.

“We could not be clearer that anyone behind such disgusting behaviour is not welcome in following the team,” it added.

Sadiq Khan, the mayor of London, said the people responsible for the abuse “must be held accountable” and that “social media companies need to act immediately to remove and prevent this hate”.

The Metropolitan Police said it was aware of “offensive and racist comments” on social media after the final and added that it would investigate.

Additional reporting by Robert Wright.