The "crucial" test as to whether the London 2012 Games is an economic success for the tourism industry begins the moment the games end, Britain was warned yesterday.

Greg Klassen, who is in charge of marketing Canada tourism internationally on the back of the Vancouver 2010 Winter Olympics, has told Britain's tourism executives and the government they will have to quickly snap out of the glamour of the games and coldly focus on "harvesting the afterglow".

Mr Klassen, the Canadian Tourism Commission vice-president for marketing strategy and communications, said: "The hard work of our strategy really began the Monday morning after the closing ceremonies because the world had a new image of Canada. It was the sort of thing where people were saying we have a new destination that we had not considered before.

"The conversion period is about two years and then we will be looking at reinvesting in our brand."

Minds automatically need to shift into thinking 'how can we sustain this for as long as we can' because the media spotlight provided by hosting the games is more than "advertising dollars can buy," he said. From the moment the games end the work needs to be about "closing the sale". The headache in the run-up to London 2012 will be trying to convince people that Britain will not be too packed and unable to cope in Olympic year.

The two-year countdown and any other milestones along the way need to be grasped as a chance to work with the media, including the unaccredited press, to update the public, Mr Klassen suggested.