A union leader fears finding a solution to a rail strike that has crippled Scottish services will not be possible because of "political interference".

Mick Lynch, general secretary of the Rail, Maritime and Transport union (RMT) said the UK-wide rail dispute involving maintenance and signal workers with Network Rail- -which owns the UK's rail tracks, stations and signals – will be prolonged “indefinitely”.

Mick Lynch, general secretary of the Rail, Maritime and Transport union (RMT), called on the Government to end its stance of refusing to get involved in talks over pay, jobs and conditions as more than 45,000 workers walked out with only 20% of services running on Thursday.

He joined a picket line outside Euston station in London as only around one in five trains were running across the country because of the walkout by members of the RMT and TSSA unions.

ScotRail has warned of four days of disruption across Scotland before a fresh round of rail strikes began on Thursday.

The nationalised train operator said the UK-wide dispute did not involve its staff but had a "major knock-on effect" in Scotland with just 11 routes open.

Some services operated on a limited number of routes between 7.30am and 6.30pm each day.

The disruption will also impact the day following each strike day, so services will be still be affected today (Friday) and Sunday.

When the RMT went on strike in July, only about 20% of services ran on strike days and some parts of the country had no trains at all.

ScotRail said only a "very limited number" of services would be operating across the central belt, Fife, and the Scottish Borders on strike days. The strike also crippled cross-border services.

As the workers walked out pickets were stationed at stations including Glasgow Central and Edinburgh Waverley where protesters chanted: "Victory to, the RMT."

Around 100 people also gathered outside Network Rail's offices in Glasgow, supporting the rail strikes.

Mr Lynch says members were "totally committed to the campaign" and said: "We will keep going until we get a negotiated settlement, and our members will decide whether it is acceptable or not".

He wrote to Transport Secretary Grant Shapps, saying: “Your government has made the decision to use taxpayers’ money to bail out private train companies from being liable for revenue lost because of industrial action on the condition the same companies comply with government instructions to hold down pay, cut thousands of safety critical rail jobs, introduce driver only trains and close ticket offices across the network.”

Mr Lynch said the union had calculated that, including the previous and forthcoming industrial action, more than £120 million of taxpayers’ money had been used to 'bail out' private train companies to date.

He said: “Using taxpayers’ money to satisfy the anti-union agenda of the Tory party and seek to break the trade unions is shameful and means the dispute will be prolonged indefinitely as the train companies don’t lose a penny as a result of the industrial action and therefore have no incentive to settle the disputes.

“Instead of waging an ideological war against rail workers, millions of voters would rather that the Government allow for a fair negotiated settlement.”

He warned  that Britain could be brought by a standstill by a wave of strikes hitting “every sector of the economy”.

The RMT general secretary stopped short of predicting a general strike, saying: “It’s not in my power, it’s up to the TUC [Trades Union Congress.

But he added: “What you are going to get is a wave of solidarity action, generalised strike action, synchronised action.

“And you’ll see it in every sector of the economy, in education, in health, wider parts of the transport system, in all sectors, the private sector as well.

“People are fed up with the way they’ve been treated. The British worker is basically underpaid and gets no dignity or respect in the workplace.

“We’ve got to change that so we get a square deal for everyone in Britain – and that’s what the unions are determined to do.”

A Department for Transport spokesperson said: “Yet again, for the sixth time since June, union leaders are opting to inflict misery and disrupt the day-to-day lives of millions instead of working with industry to agree a deal that will bring our railways into the 21st century.

“It’s clear strikes are not the powerful tool they once were and union chiefs are no longer able to bring the country to a standstill as, unlike them, the world has changed and people simply work from home.

“All these strikes are doing is hurting those people the unions claim to represent, many of whom will again be out of pocket and forced to miss a day’s work.

“We urge union bosses to do the right thing by their members and let them have their say on Network Rail’s very fair deal, which will deliver the reforms our rail system urgently needs.

“It’s time to get off the picket lines and back around the negotiating table – the future of our railway depends on it.”

Andrew Haines, chief executive of Network Rail, said he does not believe workers are “clear on what they’re striking for” and argued that the problem is not with the Government but the RMT union.

And he argued that an 8% pay rise is a “good offer” despite it falling short of inflation.

He said: “The harsh challenge we’ve got in the railway system is we’ve only got three sources of funding. The taxpayer will pay more than 50% of the railway, fares or making our system more efficient.”

He said the situation “absolutely is frustrating”.

“We’ve been talking for over 18 months. We started these talks actually with Mick’s predecessor and so there’s no lack of readiness to talk. The issue is there are some fundamental disagreements,” Mr Haines said.

“Where I have a fundamental disagreement is that I don’t think colleagues are clear on what they’re striking for now,” he continued.

“Mick mentioned pensions – that’s not an issue for Network Rail. He mentioned job security – we’ve given a guarantee of a job for every single person in Network Rail who wants a job affected by our proposals.

“Now we’ve done our very best to meet those sort of issues but the common factor here is the RMT; it’s not the Government.

“There are strikes on TfL, there are what, 13-14 train operators? Network Rail? All of those issues have been getting trapped together and I think many people striking are not clear. That’s why we think the way to solve this is to put our offer, a very decent fair offer, to a referendum of RMT members. My staff, and I think that’s the way to solve this.”