• The flag of St George flies above fans watching England's warm-up game in South Africa this week. Picture: Getty Images
With England the only team from the home nations in the World Cup in South Africa, Mr Cameron has made the unprecedented decision to exchange the flag of England for the Union Flag which normally flies over Downing Street.
Mr Cameron's comments came during Prime Minister's Questions after an appeal from a new Tory MP to get properly behind the team.
He was urged to show his support for the English team by Tory MP Nadhim Zahawi (Stratford-on-Avon), who said: "I ask you to do a great thing for the people of England and cut through the bureaucracy and nonsense and fly the flag of England over Downing Street for the duration of the World Cup."
Mr Cameron replied: "There was some question that this was going to have a cost impact but I've managed to cut through that and I can say that at no additional cost to the taxpayer the flag of St George will fly above Downing Street during the World Cup."
Then, pointedly looking up at the SNP members, he added: "For the purposes of this I'm looking at all the benches here and I'm sure that everyone in this House, no matter what part of the United Kingdom they come from, will be cheering 'come on England'."
But most SNP and Plaid Cymru MPs were shaking their heads vigorously, including Western Isles MP Angus MacNeil.
But he said the Prime Minister was right to fly the flag of St George over Downing Street.
"It's nice to see they think they can do something without Scotland," he added.
However, he insisted: "I don't want to upset anybody from other nations over who will do well in the World Cup, whether that is England, France, Germany or any other countries involved".
Ian Davidson, the MP for Glasgow South West who has just become the chairman of the Scottish affairs committee, was also diplomatic, claiming he did not mind who won because he would not be watching many games.
"As I am originally from the Borders I am more interested in rugby," he said. "But I wish England well".
The Prime Minister also failed to impress the Tartan Army. Hamish Husband, a spokesman for the Association of Tartan Army Clubs, said: "I think Mr Cameron is quite right to fly the flag of St George. I would hope that Gordon Brown would have done the same for Scotland when he was Prime Minister and I am sure nobody would have minded.
"But as far as supporting England goes, we all hope England have a good time in South Africa and lose every single game".
Mr Cameron's appeal to non-English MPs appeared to have failed to persuade politicians from north of the Border who were reluctant last night to support England.
In the House there has been some friendly rivalry about the competition, with shirts bearing the legend ABE (Anybody But England) preferred by MPs from the Celtic nation and a new SNP shirt (Scotland Not Present) worn by some English members.