The full scale of the health timebomb caused by Britain's descent into lazy lifestyles is to be exposed in a landmark report by the Government's Chief Medical Officer.
Sir Liam Donaldson will spell out for the first time how two-thirds of Britons are now so inactive - with most people, particularly women, failing to do even the minimum recommended amount of 'moderate' exercise - that they are at risk of getting cancer, diabetes and heart disease.
In an unprecedented appeal, Donaldson will urge the public to build small bursts of activity into their daily lives. He will stress how simple chores such as DIY, housework and gardening can increase energy levels, and that sports and the gym are not the only solutions.
His damning conclusions will lead to a sustained Government campaign to reduce Britain's increasingly indolent behaviour and soaring rates of obesity.
Ministers will unveil an action plan in April to try to reverse the trend. A major advertising blitz is in the pipeline, which will include characters from TV programmes such as Coronation Street taking up healthy pursuits such as gardening. ITV is already planning a 'Britain On The Move' campaign to promote walking.
The report, expected in February, will reveal the majority of the population fails to do the amount of activity which the Government and World Health Organisation says is necessary for good health. Up to half of boys and two-thirds of girls aged seven to 16 do not meet those targets, while two-thirds of adult men and three-quarters of women are just as inactive.
Tony Blair has made it clear the nation's activity levels is one of his administration's key priorities. Ministers have privately encouraged Donaldson to make his call for action as uncompromising as possible to avoid accusations of 'nanny state' interference.
Nine Whitehall departments are now working on an action plan through the cross-Government Activity Co-ordination Team (ACT), studying how countries such as Finland have introduced policy changes.
Professor Ken Fox, a social psychologist at Bristol University and an expert on how to increase activity levels, said: 'To make a real impact we have to redefine what activity means. You don't have to be sporty to be active. You could use your legs and do a bit more walking, which would really help you.
'We have been conditioned, since Victorian times, to find easier and easier ways of living. We want lots of dishwashers and lots of cars.'
But, he added, 'There needs to be a serious shift in attitudes, so that exercise is no longer seen as the enemy but as the friend. It may well help more people if they incorporate bursts of activity into daily life, rather than exhorting the nation to take up football or tennis, which only a few will do.'
Official advice is that adults should do 30 minutes of 'moderate activity', such as brisk walking, at least five days a week, and that under-18s take an hour's exercise every day. In an attempt to make exercise seem easy and fun, Donaldson will recommend several 10-minute bursts of activity during the day, and stress that exercise can improve sleep, energy and concentration.
The research shows the nation is divided between 36 per cent who play sport, and 64 per cent who like 'putting their feet up'. The inactive 44 per cent will be the main focus of the campaign.
Health and fitness experts have formed a new pressure group, Move4Health, to lobby Ministers to take dramatic action. Founder Felicity Porritt said: 'If the Government is really serious it's got to include changes to the way we live our lives.
'At the moment we are prisoners of our environment and live in a take-it-easy culture where the car is king at the expense of pedestrians and cyclists. That's got to change.'
