Airport security staff who will start a 48-hour strike today could stage weekly walkouts and leave their bosses battling to keep flights running.
A union chief revealed last night that his members could take industrial action as often and for as long as they wanted in their bitter pay and conditions dispute with management.
Highlands and Islands Airports Ltd has insisted it will be “business as usual” today, tomorrow and on Thursday – despite the absence of trained security staff at its terminals.
But it has asked passengers to arrive early and travel light to try to keep disruption to a minimum.
The company says its airports at Barra, Benbecula, Campbeltown, Inverness, Islay, Kirkwall, Stornoway, Sumburgh, Tiree and Wick in the Highlands will operate as normal.
Its terminal at Dundee will be closed for the duration of the strike by the in-house Airport Management Services Ltd (AMSL) employees, which is due to start at midday and last until noon on Thursday.
And Prospect union national secretary Alan Denney warned last night there could be further walkout if a long-term solution was not found.
He cut short his holiday to hold discussion with Hial chiefs, but the talks broke down without a peace deal being struck.
Mr Denney said: “We’ve notified the company that we’re taking what’s called ‘discontinuous action’.
“The ballot result means we can take strike action on Tuesday and then we can continue to take strike action as often, as frequently, as we wish.
“It’s quite possible that we could be taking further action next week or the week after.
“We don’t need a further ballot, the law’s very clear on that.”
He added: “There are cases of unions taking action that extended over several months on the basis of one ballot.
“We’re not planning on that, for goodness sake. We’re hoping this will be an issue that’s resolved quite quickly.
“But we are entitled, in law, for example to take two days action every week for the next goodness knows how many weeks.”
Mr Denney accused Hial of failing to seek Scottish Government approval for an improved offer to the AMSL workers.
He will be at Inverness Airport today to meet the strikers – or the management if they come up with a new offer.
Hial has in turn accused the union of setting an “unreasonable deadline” while it pressed for more time to discuss a potential compromise deal with government agency Transport Scotland.
The company’s managing director, Inglis Lyon, insisted the government “have been kept fully informed throughout”.
He said the immediate focus was on minimising disruption to passengers.
Any further action, he said, would be discussed between the company and the union at a later date.
He added: “We would like to thank passengers, in advance, for their co-operation and understanding during this period, and we would also like to thank the local teams for their support and helping it be business as usual.”
The union claims that in the six years since Hial took security in-house, it had “failed to agree equal pay, holidays and sick pay for airport security workers”.
Prospect represents about 120 of the 160 staff affected. It wants a 5% pay increase and parity for its members with higher paid staff at Sumburgh Airport.
In a ballot last month, 87% of Prospect members working for AMSL backed a walkout.
Their role covers a range of security checks including carrying out searches and operating X-ray equipment at terminals.
Hial claims there will be “no extra costs incurred” during the strike because there are “fully trained colleagues” available to cover for the AMSL: workers.
Mr Lyon said: “We have staff from other parts of the business trained to deliver the security function at the airports impacted by the strike.
“There will be no extra costs incurred as a result of the strike.”