MOTORISTS are to be banned from two of Scotland's most famous streets under radical plans to cut pollution levels and reduce accidents.

Edinburgh's transport guru, Councillor David Begg, is leading the move which will see cars banished from Princes Street and one of the busiest sections of the Royal Mile closed to traffic.

Mr Begg, who is a transport adviser to Deputy Prime Minister John Prescott, last night came under fire from one of the country's leading motoring organisations, the AA, which described it as a ''driver's nightmare''.

However, Mr Begg, who has championed the Government's aim of encouraging motorists on to public transport, said that the time had come to give the streets back to the pedestrians.

He said yesterday that Edinburgh had the fastest growing rate of car ownership in the United Kingdom and Princes Street was recovering from one of the highest accident rates in Scotland.

''It is time to make some clear decisions and hard choices and ask ourselves why we have tolerated the carnage and unacceptable levels of pollution on Princes Street for so long.

''We hear a lot about the poor motorist but what about the poor pedestrian, cyclist or bus user for that matter? We want to create a high quality shopping environment on Princes Street, where pedestrians can breathe clean air and shop safely without coming into conflict with cars,'' he said.

On Monday, the ruling Labour administration will move to launch legal proceedings to implement a complete ban on all cars from the historic thoroughfare. Two years ago, traffic was restricted to buses, taxis, and cycles on the east bound carriageway and the latest development extends that to the west bound route between Waverley Bridge and the West End.

The restrictions, if passed by the transportation committee, could be in place by late 1999, and will greatly enhance the council's plans to build a #100m underground mall below Princes Street.

By next summer, it is also envisaged that all traffic, except buses, will be banned from the Royal Mile between the City Chambers and Cockburn Street as councillors vote to put the plans out to public consultation at the same meeting next week.

The council expert heading up the Princes Street project, Mr Alex Macaulay, said innovative enforcement measures could also be introduced for westbound traffic.

He said: ''One option under discussion is to make it totally self enforcing so that the police do not have an enforcement problem.

''That may involve all buses and taxis being fitted with transponders which would automatically trigger the lowering of bollards or a car-park style swipe card being introduced on Princes Street.''

However, while the plans have received the backing of the business community, they provoked an angry response from the AA and residents living on the diversion route through Queen Street and the city's New Town.

A spokesman for the AA said: ''While this may be of benefit to the pedestrian, this could well be a nightmare for motorists. Schemes like this do not address the problems of congestion, they just shift it.''

The scheme has been tested on a #100,000 computerised assimilator, which apparently shows that the surrounding streets will cope with the strain.

However, the local councillor, David Guest, dismissed the plans as flawed, adding that the council had failed to take into account traffic calming measures for the Scottish Parliament, which will include pedestrianising part of Holyrood Road.

He added: ''This council seems to assume they can use Edinburgh for some crazy and half-baked national transport experiment.''

Ms Felicitas Macfie, who sits on the New Town Forum for Urban Living, accused Mr Begg of creating ''a citizen's enraging scheme''.

She said: ''This is not about encouraging people out of their cars, it's about David Begg riding roughshod over the citizens of Edinburgh and trying to further his career.''

Meanwhile, ambitious plans for a retail and leisure development to the east of the city at Newcraighall are expected to be rejected by the council's transportation committee.