Bus drivers in the West of Scotland are beginning a six week strike against their employers in an escalation of an ongoing pay dispute.

More than 400 Stagecoach drivers at depots in Ayr, Arran, Ardrossan and Kilmarnock will not return to work until 21 July, with the operator running a limited service as a result.

The Unite union said the action was due to the company not offering any improvement on a “simply unacceptable” 4% offer from last November.

Stagecoach said any pay offer had to preserve the viability of bus services in the area.

Unite previously held three separate 24 hour strikes in May and June, but the latest action escalates the dispute by running consecutively for six weeks.

The union has claimed the drivers involved are among the poorest paid across Stagecoach’s UK operations.

Siobhan McCready, an industrial officer at Unite, said the most recent Stagecoach offer had strings attached to it.

She stated: “The drivers are being asked to fund a pay rise by working longer hours, taking longer unpaid breaks and losing a week of annual leave.

“This is simply unacceptable, and it will not be tolerated by Unite.”

Ms McCready added that the prolonged action could be ended if Stagecoach listened to workers.

Stagecoach said passengers should check its website for updates to services throughout the strike.

Services in Cumbernauld and Dumfries and Galloway are unaffected by the industrial action.

The company said it would aim to keep as many services running by working with drivers from other companies.

A spokesperson said: “Regrettably, the industrial action will disrupt our services and inconvenience our customers.

“We’re working hard to minimise the impact of this disruption, but unfortunately, the limited services we’re running will affect customers travelling in and around Ayrshire.”

The company previously stated it was committed to reaching a “fair and sustainable agreement – one that supports our employees while ensuring the long-term viability of our services across west Scotland.”

The previous one day strikes proved controversial after Unite claimed members were told by Stagecoach to stay away from picket lines as working staff may be intimidated.

Ms McCready claimed the company had been using CCTV at depots to monitor picket lines.

Stagecoach insisted it had simply advised employees that any industrial action “should be carried out peacefully and within the law”.

In April Unite said it would consider legal action against Stagecoach after the company said it would cancel bus drivers’ holiday dates during planned strikes.

The threat was later dropped due to talks resuming in an attempt to solve the dispute.

This is a local dispute of national significance.

It is a confrontation between a major trade union and part of a transport giant.

For both sides, there are high stakes.

Three one day strikes over the past fortnight have not brought a resolution to the pay row.

Moving towards six weeks of continuous strike action is a big escalation and represents the kind of industrial action which is now relativity unusual.

It represents a willingness by the workers to make a big sacrifice in their battle for a better pay offer.

Unite the Union is prepared to support them through any hardship.

But will support for the strike be maintained?

How will Stagecoach and its customers respond to ongoing disruption?

Generally industrial disputes are settled by compromise.

Neither side gets everything they want.

However those compromises usually require one side to blink first.