County councillors say the government must be kept under pressure to find alternatives to Operation Stack and not be allowed to let the issue drift off the agenda.

The warning came today as a series of options to provide a solution - with an eye-watering price tag of £468m - were debated at County Hall.

And there was severe criticism of the use of the former Manston airfield as an emergency relief lorry park, with the cross-party committee saying it should be stopped.

There were also misgivings over one of the key elements of the plans, an option for a lorry park capable of holding 4,000 HGVs.

It has emerged that Highways England is expected to announce by the end of this month how it intends to respond to the government’s direction to find alternatives to Operation Stack.

It is thought that it will confirm plans to reinforce the hard shoulder of stretches of the M20; set out a way of keeping the M20 open to traffic in both directions and propose possible sites for a holding area capable of storing up to 4,000 HGVs.

Labour councillor Dr Mike Eddy said that using Manston on a temporary basis would prove to be a disaster for the area.

“If Manston is used, not only will you have the route south of the M20 be blocked, you will have the M2 and A2 blocked by traffic and HGVs. It would be a total disaster.”

He added: “I am pleased that it is now on the national agenda. It is not a Kent problem but one for the whole national economy.”

The criticism over Manston was echoed by Ukip spokesman Cllr Mike Baldock. “There is no sensible way of getting lorries to Manston. I know something has to be done but we should not come up with ideas just for the sake of it.”

Ashford councillor Andrew Wickham said the focus needed to be kept on related plans for a series of smaller lorry parks that would open all year round.

“One concern is that while Operation Stack happens part of the year, illegal parking by lorries goes on 365 days a year. There will be enormous opposition to a large park.”

However, councillors broadly welcomed the plans but underlined that it should not be Kent taxpayers who picked up the tab.

Speaking after the meeting, Kent County Council cabinet member for transport Cllr Matthew Balfour said: “Through all the work we have been doing with the government, we have the feeling that we have their interest in pushing ahead.

"The Prime Minister said that he wanted things done at pace - we have been doing everything we can at pace to find solutions.”

He was not concerned that the issue would drift off the political agenda.

“It is still getting the interest that it did in the summer. Inevitably, there is less media interest - that does not mean government officials and ministers and KCC officers are doing all they can to move this on.”