Blair, under pressure to match the patriotism of opposition leader David Cameron, who pedals to work with an England flag flying from his bicycle, also sent a handwritten good luck message to England coach Sven-Goran Eriksson.

"It's a great squad, well led, well managed, and as you know with everyone hoping for great things. That's a tremendous responsibility but also a fantastic opportunity," Blair wrote.

"Spirits and confidence are deservedly high. We will all be cheering you on," he added. The flag of St. George -- a red cross on a white background -- will also flutter above the prime minister's official residence on Downing Street on days when England play in Germany, Blair's spokesman said. England open their World Cup campaign against Paraguay on Saturday.

As usual before a major tournament, millions of soccer-mad English fans have attached England flags to their cars or homes.

Politicians have not held back despite criticism that flying the England flag -- rather than the British Union Jack -- is a snub to the people of Scotland, Wales and Northern Ireland which are also part of the United Kingdom.

Sports minister Tessa Jowell is proudly flying two England flags from her official car.

Blair's spokesman said that displaying the England flag was in no way a slight on Scotland, Wales or Northern Ireland.

"There is only one nation, of the countries that make up the United Kingdom, taking part in this World Cup and therefore it is right to recognise the significance of that occasion," he said.