England manager Gareth Southgate insisted the Three Lions crest was the most important part of the national team’s shirt as the Football Association faced criticism of the latest kit from Prime Minister Rishi Sunak and Labour leader Sir Keir Starmer.

The shirt’s manufacturer Nike has altered the appearance of the St George’s Cross using purple and blue horizontal stripes in what it called a “playful update” to the shirt ahead of Euro 2024.

Sunak warned Nike “should not mess” with the flag, while Starmer urged Nike to “reconsider” the design.

Southgate, though, was more interested in the iconography surrounding the traditional Three Lions badge rather than being drawn on the “artistic take” on the St George’s Cross.

He said: “It’s not been high on my list of priorities but that depends which bit it is (causing the controversy) because I don’t know if the debate is about the St George flag needing to be on the England shirt, because obviously it hasn’t always been.

“I think the most important thing that has to be on an England shirt is the Three Lions, it’s our iconic symbol, it is what distinguishes us not only from football teams around the world but from England rugby and England cricket.

“It’s the thing that, when I put my shirt on at Burnham Beeches, 30 years ago, I looked in the mirror – and I clearly don’t look at my face too often when I do that – but the Three Lions really stood out.

“So I suppose what you’re really asking is, should we be tampering with the Cross of St George?

“But in my head, if it’s not a red cross on a white background, it isn’t the cross of St George anyway, so it is a hard question to answer really because it is presumably some artistic take on, which I am not creative enough to understand.”

The Football Association stood by the controversial design of the new kit and said it was “very proud” of the red and white St George’s Cross but gave its support to the new look.

“The new England 2024 home kit has a number of design elements which were meant as a tribute to the 1966 World Cup-winning team,” a spokesperson said.

“The coloured trim on the cuffs is inspired by the training gear worn by England’s 1966 heroes and the same colours also feature on the design on the back of the collar. It is not the first time that different coloured St George’s Cross-inspired designs have been used on England shirts.

“We are very proud of the red and white St George’s cross – the England flag. We understand what it means to our fans, and how it unites and inspires and it will be displayed prominently at Wembley tomorrow – as it always is – when England play Brazil.”

The Prime Minister was asked about the kit design on a visit to Derbyshire 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,” Sunak said.

“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.

Nike issued a statement on Friday afternoon insisting it “was never its intention to offend” with the design but did not indicate any intention to change it.

“We have been a proud partner of the FA since 2012 and understand the significance and importance of the St George’s Cross and it was never our intention to offend, given what it means to England fans,” the statement read.

“Together with the FA, the intention was to celebrate the heroes of 1966 and their achievements. The trim on the cuffs takes its cues from the training gear worn by England’s 1966 heroes, with a gradient of blues and reds topped with purple. The same colours also feature an interpretation of the flag on the back of the collar.”

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.