Cars should be banned from the school run where the distance is walkable to fight obesity in parents and children, the authors of a new report suggest.

In 1982, adults drove an average of 55 miles a year each to take their offspring to school, but by 2005 it had risen to 82 miles, the Institute for European Environmental Policy said. Setting car exclusion zones around schools would encourage families to walk short distances instead, benefiting their health and the environment by reducing carbon dioxide emissions.

The report's lead author, Adrian Davis, said children should be taught that walking was a better option so they would encourage their parents to ditch the car in the morning.

"Children, particularly young ones, are very keen to do the right thing," he said. "We need their pester power."

Various governments had shied away from a national walking policy, he added.

Unfit for Purpose: How Car Use Fuels Climate Change and Obesity, calculated that 38% of all journeys under two miles - equivalent to a brisk 30-minute walk- are taken by car.

Almost an hour a week is switched from walking to car travel once a vehicle is available, which the authors said was in itself enough to account for much of the rise in obesity among adults in recent decades.

If a typical British adult were to return to walking for that hour it would prevent them gaining up to 12.7kg (28lb) over a decade, as well as cutting CO2 emissions by nearly a sixth.

The authors also want to see people using cars less for shopping. The average adult mileage for shopping was 125 in 1989, but had soared to 444 in 2005.