YOUNGSTERS yesterday called on the Government to impose stiffer penalties on speeding motorists as they helped launch national Road Safety Week.

A group of 73 children - representing the number of children killed by speeding vehicles on Britain's roads each year - descended on London atop a double decker campaign bus.

Among them was Sophie Graham, aged ten, of Gateshead, who was the victim of a hit-and-run incident in July last year.

Sophie was knocked down and left lying on the road by banned driver Garry Wilkinson, 30, as she paraded for friends in the bridesmaid's outfit she had worn to her aunt's wedding the previous day.

She suffered a double fracture to her skull and a double fracture but defied doctors' predictions and made a full recovery.

Yesterday, she knocked on the door of 10 Downing Street and helped to hand over a manifesto from road safety group Brake, calling for bigger fines, more speed cameras and wider education awareness initiatives.

Children are the theme of this year's Road Safety Week, organised by the charity after 218 youngsters died on the nation's roads last year - a 14 per cent rise on the previous year.

About 3,400 people die every year in road accidents.

It is estimated one in three cases involve excessive speed - resulting in the figure of 73 for yesterday's campaign.

Brake chief executive Mary Williams said: ''Deaths caused by speed are a simple case of kinetic energy - the faster we go, the harder we hit and more children are dying - inside vehicles as well as on foot and bicycles.''

The key message of this week is "safe streets for the sake of our children" and will see a host of events in 10,000 schools up and down the country.

The Government has pledged to cut the number of child deaths on the roads by half by 2010.