Prime Minister Rishi Sunak says kit manufacturers “should not mess” with the St George’s Cross as he waded into a row over the new England shirt.

Nike has altered the cross using purple and blue horizontal stripes in what it called a “playful update” to the shirt ahead of Euro 2024. The US firm said the colours were inspired by the training kit worn by England’s 1966 World Cup winners.

Former England winger John Barnes told the PA news agency the row over the flag was “much ado about nothing”, but Sunak said on Friday: “Obviously I prefer the original, and my general view is that when it comes to our national flags, we shouldn’t mess with them.

“Because they are a source of pride, identity, who we are, and they’re perfect as they are.”

Labour leader Sir Keir Starmer called on Nike to reconsider, and told The Sun: “I’m a big football fan, I go to England games, men and women’s games, and the flag is used by everybody. It is a unifier. It doesn’t need to be changed. We just need to be proud of it.

“So, I think they should just reconsider this and change it back. I’m not even sure they can properly explain why they thought they needed to change it in the first place.”

A petition on Change.org calling for a design change had already attracted more than 21,000 signatures by noon on Friday.

However, former national team star Barnes could not understand what all the fuss was about.

“I don’t get involved in culture wars any more but this whole furore…I didn’t even know there was a St George’s cross,” he said at a Forever Reds golf day ahead of the Liverpool Legends’ game against Ajax on Saturday, which is expected to raise over £1million for the LFC Foundation.

“If they were going to change the three lions then that’s a debate to be had. I don’t see what the fuss is. I think it’s a much ado about nothing.

“They are not changing the colour of the shirt, the lions are still there. If they were going to change the national flag for England and change the colours then that’s a proper debate to have.”

The kit pricing has also been criticised.

An “authentic” version costs £124.99 for adults and £119.99 for children while a “stadium” version is £84.99 and £64.99 for children.