Prime Minister David Cameron and US presidential candidate Mitt Romney have both spoken out about the flag row that saw the North Korean women’s football team refuse to take to the field at Scotland’s national stadium.

Speaking at an Olympic press conference today, Mr Cameron said the South Korean flag being wrongly shown on a big screen at Hampden Park before the North Korean women’s football match last night was “unfortunate and should not have happened”.

And asked about Olympic security issues and the error over the North Korean team flag as he met Labour leader Ed Miliband in Westminster today, Mr Romney replied: “It is impossible for absolutely no mistakes to occur.

“Of course there will be errors from time to time, but those are all overshadowed by the extraordinary demonstrations of courage, character and determination by the athletes.

“The Games are, after all, about the athletes, the volunteers and the people of the community who come together to celebrate those athletes.

“As soon as the Games begin, we all forget the organisers and focus on the athletes.”

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Mr Romney has also questioned Britain’s readiness to host the Olympic Games.

Ahead of his meetings with Mr Cameron, Mr Miliband and Nick Clegg he told US television there were “disconcerting” signs. Mr Romney told NBC News: “It’s hard to know just how well it will turn out. There are a few things that were disconcerting.

“The stories about the private security firm not having enough people, the supposed strike of the immigration and customs officials - that obviously is not something which is encouraging.”

Barack Obama’s Republican challenger is expected to stress his commitment to the “special relationship” as he uses the trip to raise funds and canvas support among London’s large American community.

But in the interview he also called into question whether the British people were behind the Games.

“Do they come together and celebrate the Olympic moment? And that’s something which we only find out once the Games actually begin,” he said.

Last night the North Korean women’s football team refused to take to the field in a row over the display of the flag of their neighbouring adversary South Korea.

In an incident one foreign journalist described as “one of the more bizarre moves in Olympic history” the North Korean women’s soccer team stayed in their Hampden changing rooms for 40 minutes in protest at the flag blunder.

The London Organising Committee of the Olympic Games (Locog) said an official apology will be made to the North Korean team and the National Olympic Committe, and steps will be taken to ensure such an incident never happens again.

Relations between the two Koreas have been tense since the armistice in 1953 that brought an end to fighting in the Korean War, which cost two million lives.

The London 2012 match between North Korea and Colombia was scheduled to start at 7.45pm but the North Koreans became angry because the South Korean flag had been flashed on the stadium’s giant screens. As the players’ names were displayed in a video package, the flag shown beside them was that of South Korea, rather than North Korea.

As Colombia lined up in the tunnel, the North Koreans stayed in their changing rooms.

After frantic behind-the-scenes discussions, both teams finally took to the field for a warm-up, 40 minutes after they were due to kick off. They finally kicked off at 8.50pm – one hour and five minutes later than scheduled.

With the world watching, the incident will be an embarrassment to officials who have struggled to sell tickets for the five days of London 2012 football matches at Hampden.

A Locog spokesman said: “Ahead of the women’s football match at Hampden Park, the South Korean flag was shown on a big screen video package instead of the North Korean flag.

“Clearly that is a mistake, we will apologise to the team and the National Olympic Committee, and steps will be taken to ensure this does not happen again.”

An Olympic Broadcasting Service insider said: “This was a stadium presentation issue involving Hampden. It is their stadium, their screen and they control it.”

A spokesman for Fifa, the world governing body of football, added: “This was a Locog issue, not a Fifa issue. They eventually showed the right flag but the North Koreans were still not happy and said they must show their flag again.”

Only a few thousand fans were in the stadium for the match, filling less than 5% of the ground capacity, but they let their displeasure be known before leaving the stadium, booing or slow hand-clapping. There were further jeers as both teams took to the field.

While some fans had complained about the lack of information, an announcement was made, 30 minutes after the North Korean protest began.

Fans were told: “We apologise for the delay caused by an issue behind the scenes. We are trying to resolve this and will keep you updated.”

One spectator, Alastair McPhee, who supplies blind and partially-sighted clients with free audio recordings of papers, magazines and television, said: “There are only so many times the crowd can do the Mexican wave and many are now getting fed up and leaving.”