Brigitte Chaudhry's 26-year-old son, Mansoor, died nearly three years ago after the accident in front of St George's Cathedral in Lambeth, south London.
She started her campaign after a magistrate refused to issue a private summons on her behalf against the van driver, Nicholas Sansom, for causing death by reckless driving. A plea of guilty to a lesser charge of careless driving, brought by the Crown Prosecution Service, was accepted.
Sansom, of New Eltham, south-east London, was fined pounds 250 with eight penalty points which, added to existing points, led to a six-month driving ban.
Mrs Chaudhry, 52, a teacher from Willesden, north-west London, launched an appeal to the High Court and became an outspoken critic of the law's 'casual' attitude to traffic light violations which, she says, are accepted as 'forgiveable slips'.
Yesterday, two judges rejected her lawyers' argument that the historic right of an individual to prosecute had left the magistrate with no option but to issue the private summons.
Lord Justice Kennedy, sitting with Mr Justice Bell, said magistrates should be very reluctant to take such a step when charges had already been brought by the Crown unless there were special circumstances such as bad faith on the part of the prosecution.
He said it would be an 'odd situation' if the DPP's decision to charge a person with an offence which was not the most serious in the circumstances could be overriden by a member of the public.
Mrs Chaudhry said the decision would be considered by her counsel, Anthony Scrivener QC, with a view to taking the case to the House of Lords. 'I am very disturbed by this judgment which shows there was considerable fear that members of the public would interfere with decisions of the CPS,' she said.
John Knight, co-founder of the Campaign Against Drinking and Driving, said: 'This decision means a motorist can ignore traffic lights and kill somebody and the law will take no proper action. It is a recipe for mayhem on the roads.'Reuse content