The organizers of the London Olympics conceded defeat in selling all the tickets for the football tournament as they revealed plans to slash the capacity of some stadiums.

LOCOG said more than one million tickets were left unsold, but that figure has been cut in half by reducing capacity at venues including the Millennium Stadium in Cardiff. The changes mean 250,000 tickets are currently available.

A further 200,000 football tickets are due to go on sale after being returned by Olympics committees from around the world. The top tiers of stadiums will be curtained off to hide the empty seats.

"We are planning to reduce capacity across the venues by up to 500,000 tickets across the tournament," a LOCOG spokesman said.