And the union’s branch secretary for Dundee, Rory Malone, did not dismiss the idea that further one-day, all-out strikes might also be called in the middle of the week-long protests, causing even greater chaos across council services.

Mr Malone said the latest wave of industrial action was a direct response to a refusal by the Convention of Scottish Local Authorities to accede to workers’ demands for a fairer pay deal.

He said some Labour politicians locally, at Holyrood and Westminster, had voiced their support for an improved pay claim and the public also appeared to be behind the council workers’ actions.

He told the Tele, “We’re in this for the long haul. It’s easier to keep going knowing we have people behind us. It was a huge boost so many low-paid workers took part in Wednesday’s day of action, sacrificing pay for the cause.

“We’re prepared to continue with the struggle and the other local authority unions are also solid.”

Unions Unison, Unite and the GMB, are seeking a 5% or £1000 rise — whichever is greater — but their demands have been rejected by Cosla negotiators representing all 32 councils. Cosla have offered 2.5%, which, given the escalating cost of living, is being viewed as effectively a pay cut by the unions.

They have realised asking council workers to give up pay in all-out strikes is unsustainable in the long term and so have decided to target vulnerable council services with action by limited numbers of employees. The unions have said they are prepared to make good any loss of wages.

There have already been two one-day stoppages, but the campaign will move into different territory on Tuesday October 7 when the 50 call- handlers stop work. Mr Malone said the main switchboard–the first port of call for most phone users–will be out of action and people will be unable to contact the council by phone across a range of council services including housing benefit inquiries and housing repairs.

The call-handlers’ action will continue right through until Monday, October 13, when another section of council workers will come out for a whole week. The Monday after that, it will be the turn of a different batch of workers to stage a seven-day strike.

The unions declined to say which other council services would be hit by the second and third rounds of selective action.

Mr Malone added, “This will cause maximum disruption. People will not be answering phones, and things like housing repairs will go unlogged. Our members are very angry at the lack of response from the employers and we intend to keep this going as long as it takes. It is possible there will also be more one-day stoppages at some point during the three weeks of selective action.”

The two earlier days of action — one in August and the other just three days ago — had a severe impact on many council services. On Wednesday, the city’s secondary schools were only open for senior pupils, all but four nursery and primary schools were closed, and people were unable to pay council tax, make a housing inquiry, schedule a repair or book a show at one of the city’s performance venues.

The first one-day strike is understood to have had a more serious impact on council services, but Mr Malone said he believed this week’s strike had greater support from the workforce.

A Dundee City Council spokes- man said they were seeking clarification from Unison about strike plans for the city and declined to comment further until then.

The position in Perth and Kinross regarding possible action by call-handling staff was today still unclear.

However, a council spokesman said the authority is monitoring the situation.

“We are waiting to hear from Unison about any plans at a local level for future industrial action.”

Although Angus is also expected to be hit by the latest phase of the strike, a council spokesperson said, “We have received no notification from the unions that there is to be any selective action.”

Fife Council were also asked to comment, but had not done so at the time of going to Press.