OLYMPICS: The chances of a London bid for the 2012 Olympic Games received a much-needed boost yesterday after the British government advisers did a U-turn on claims there are no benefits from staging major sports events.

The draft report from the strategy unit had made the claims but when the final report was published yesterday that section had been replaced by one saying staging events such as the Olympics can be beneficial under certain conditions.

With the government already claiming the cost of hosting the Games could be more than double the £2 billion figure produced by independent consultants, such comments could have sounded the death knell for those backing a bid.

The report, titled Game Plan, now says there can be benefits provided the government are involved from the start and as long as costs, benefits and risks are clearly worked out. On the day of the first meeting of the group of ministers set up to evaluate whether to make a bid for the 2012 Games, the changes to the document remove a source of potential embarrassment to the government.

Tessa Jowell, secretary of state for Culture, Media and Sport, revealed a strategy for bidding for major events over the next 20 years would be drawn up. She said: "Mega events such as the Olympic Games or World Athletics Championships can only succeed if central government are closely engaged from an early stage . . . A 20-year strategy for bidding for mega events will be part of our wider vision for sport over the next two decades."

The decision on 2012 is to be taken at the end of January but with the government estimating the cost of staging the Games at more than £5 billion the Treasury will have to be convinced of its value.

The British Olympic Association claim such an estimate - which would mean up to £3 billion coming from the public purse - is very pessimistic.

The strategy unit report also calls for a change in the way sports are funded to cut down on bureaucracy, increasing participation of the population in physical activity and improvements in the way funds are allocated for elite athletes in different sports.