A red, patchwork flag will be raised and flown at half mast this week to mark the start of an appeal for a permanent national memorial to road accident victims.

The flag will be made up of pieces of material donated by those bereaved by traffic accidents.

The London flag-raising, on Saturday, August 16, signals the beginning of the memorial campaign by RoadPeace, the national charity for traffic victims.

The group is being supported by the Metropolitan Police, the Association of Chief Police Officers and other bodies.

Saturday is the 101st anniversary of the first fatal road accident involving a petrol-driven car. The first victim was Ms Bridget Driscoll, 44, who was hit by a car on her way to a fete at Crystal Palace in south London.

''Many families have been torn apart by road death and injury and most people know someone affected in this way,'' said RoadPeace founder Brigitte Chaudry.

She went on: ''The red flag symbolises the sewing back together of the fragments from these ruined lives.''

Among those attending Saturday's ceremony will be Brent East Labour MP Ken Livingstone, who is a patron of RoadPeace.

The organisation is pressing for churches to offer special services for road victims on the third Sunday in November each year, starting on November 16, 1997.