Plans to introduce tolls on one of Scotland's busiest motorways came under fire yesterday

Mr Peter Burdon, chief executive of Glasgow Chamber of Commerce, is calling for motorists using the M74 to pay a toll of about 50p.

The cash raised would be used to pay for the #176m M74 extension scheme and other transport projects.

But the proposals have been criticised by motoring organisations and the Scottish National Party.

Mr Stewart Hosie, SNP transport and telecommunications spokesman, described the plan as ''absolutely stupid''.

He added: ''This motorway extension can be built, but it's about political priorities. Gordon Brown needs to stop playing the iron chancellor and release some of the billions in his war chest. ''Trunk roads should be part of the general roads network for use by everybody. A toll would prevent everyone from accessing the motorway and would therefore create a two-tier traffic system.''

Mr Burdon said the long-awaited M74 scheme could only be completed if the toll was introduced. ''The cost of the M74 completion has now been reduced considerably, but it is still too much for the Treasury to bear unless tolls are introduced,'' he said.

''Given the choice of road with toll or no road at all, I would opt for the road any time, so long as the toll is not too steep.''

Mr Burdon is campaigning to set up tolls at major entry points to the network, which include the M8, M80, M77, M74 and the M73.

But he stressed that collected tolls would be ringfenced for transport-related projects and to improve public transport.

Ms Sue Nicholson, spokeswoman for the RAC, warned of increased congestion around Glasgow if tolls are introduced. ''We are not in favour of tolls on the M74 and we don't see it as being a workable proposal,'' she said. ''There has to be alternative routes for people. That is one of the things that we would insist on.''

Mr Neil Greig, roads and environment officer for the AA, said drivers would need an incentive to use the motorway. ''It has been proved that people will drive miles out of their way to avoid paying a toll,'' he said.

Councillor Walter McLellan, convener of Glasgow City Council's roads and transportation department, described the proposal as ''premature''.