Britain may be basking in post-Beijing success but our analysis today, in support of the Standard's 2012 Sporting Legacy campaign, shows that many London children have little opportunity to do sport at school. That this should still be so is a damning indictment of ministers' promises on school sport.

Labour's 1997 manifesto promised at least two hours of school sport or PE a week. In 2001, Tony Blair promised again to meet the target. In 2004 he admitted on TV that only 60 per cent of schools had reached the target but claimed that by 2006, three-quarters of schools would be offering at least four hours. Last week, Culture Secretary Andy Burnham promised a total of five hours a week of sporting activity overall, including coaching.

Now, in nearly half the capital's boroughs, even the less ambitious target of two hours is still not being met. What is more, the figures include after-school sport, which is not compulsory. The Government has added a new target of five hours a week including two hours within curriculum time plus after-school provision, but this makes little sense when the initial two-hour milestone has not been reached.

Gordon Brown seemed to grasp that sport mattered when he praised Britain's Olympians last month. Yet his £45 billion Building Schools for the Future programme is in fact removing swimming pools from many schools. The colossal BSF scheme is a once-in-a-lifetime opportunity to build better PE and sports provision into schools: ministers, local authorities, school governors and heads must ensure architects see sports halls, pools and outdoor space as a necessity, not an optional add-on.

Making two hours a week of PE or sport a formal part of the curriculum would also help, though school timetables are already crammed with other requirements. Only a determined assault against objectors in the teaching unions, more flexibility in the national curriculum and funding where in-house or local facilities are still poor, would tackle the ­problem.

Even those in the teaching establishment who dislike competitive sport must now acknowledge the threat posed by obesity and lifestyle-related illnesses to today's children, some of whom can expect shorter lives than their parents. Yet when Schools Secretary Ed Balls presented his wide-ranging Children's Plan to the Commons last year, he did not even mention school sport. Ministers may mouth warm words about the importance of sport but they have totally failed to deliver on their promises. A major rethink of how to provide sport in schools is needed. The Government's record to date is a disgrace.