Plans for a Glasgow congestion charge could derail the SNP’s campaign in Rutherglen and Hamilton West, a campaign source had admitted. 

If the proposal goes through, it could see thousands of locals in the South Lanarkshire seat forced to pay a levy to enter Glasgow city centre.

One frustrated SNP campaigner said they couldn’t believe their colleagues in George Square had floated the idea in the middle of a hotly contested by-election.

READ MORE: Glasgow Council considering congestion charge

In an interview with The Herald over the weekend, Glasgow City Council's depute leader Ricky Bell said it was only fair that people who drive in and use services "free gratis" should contribute to the running of the cash-strapped city.

London’s congestion charge, which was brought in 20 years ago, sees drivers pay £15 to get into the centre.

Asked about the congestion charge during a campaign event on Monday, Katy Loudon the SNP’s candidate in the constituency, said it was “very much a matter for local councils.”

“The Scottish Government have said that as well that they're going to offer local councils support to make sure that they are putting funds in place to encourage sustainable forms of transport, like active travel, like people coming in, using train services.

“We've got new facilities so in in Cambuslang train station, we've got a big new parking and ride open.

"We've got a big new park and rides expanded in Newton Farm which are two of the busiest train stations in this area.

“So it's very important that we're getting the balance correct. We do need to encourage people to take more sustainable forms of transport into the city centre, but it's very much a matter for local councils.”

READ MORE: SNP ministers urged to use congestion charges to fund public transport

Asked what she would say to SNP colleagues in Glasgow, Ms Loudon replied: “Well, this is actually a responsibility for the Scottish Government. But of course, if I'm the MP then I'm going to reflect the views of my constituents and make sure they're speaking to their correct representative on that.

“And it is difficult times just now for people with the cost of living crisis, of course it is, and that's why during the Programme for Government announced by the Scottish Government last week, the focus is very much on looking at the support that can be put in place and it was unashamedly an anti-poverty but also a fairer and a greener Program for Government and that'll be reflected in the budget when it happens later in the year as well.

“But there is very much Scottish Government support for looking at forms of travel and the free bus passes and other initiatives which are similar to that are part of that story.”

A campaign source told The Herald they were stunned by Councillor Bell’s suggestion.

“We’re in a real scrap here and our prospects are not being helped by Ricky telling our voters that under the SNP they’ll have to pay an extra £5 a day or whatever to get into to their work. It's madness. It does our chances here no good.”

Labour candidate Michael Shanks said Ms Loudon needed to come out publicly and oppose the charge. 

He said: “Thousands of people in Rutherglen and Hamilton West are potentially facing congestion charges to enter Glasgow in a time of cost of living crisis – but Katy Loudon cannot bring herself to oppose this attack on the people of the area.

“Katy Loudon needs to show what side she is on – that of her party bosses in Holyrood and on Glasgow City Council, or the side of the people of Rutherglen and Hamilton West.

“It is unthinkable that the SNP should propose this tax on working people in the middle of a cost of living crisis."