LONDON, March 22 (Reuters) - National flags should not be "messed with", British Prime Minister Rishi Sunak said on Friday, after Nike's ( NKE ) decision to use an altered design of the St George's Cross on England's soccer shirts angered some fans.

Nike ( NKE ), which makes the kit for England's national soccer teams, unveiled its new design this week, which it said paid homage to the country's 1966 World Cup-winning men's team.

It features the St. George's Cross, which is red on a white background and is England's national flag, but in shades of red, blue and purple on the back of the shirt collar.

Nike ( NKE ) called the change a "playful update" that was meant to "unite and inspire", adding that the design "disrupts history with a modern take on a classic".

But the move has spurred calls from some fans writing on social media and calling in to radio shows to scrap the new design.

With a national election expected in Britain this year, in which cultural issues are likely to feature prominently, politicians from across the spectrum have commented on the design.

"Well, obviously, I prefer the original," Sunak told reporters. "My general view is that when it comes to our national flags, we shouldn't mess with them, because they're a source of pride, identity, who we are, and they're perfect as they are."

Opposition Labour Party leader Keir Starmer told The Sun newspaper that Nike ( NKE ) should reconsider the design.

Former England goalkeeper Peter Shilton, who played for the national team at three World Cups, said there was no need to change the flag.

"I think we see a lot of changes these days with different things and I just think the colours for England, like the Three Lions, it's traditional," he told BBC radio.

Nike ( NKE ) did not immediately respond to a request for comment on Friday.

"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," a spokesperson for the U.S. sportswear giant told media this week. "The same colours also feature an interpretation of the flag of St George."