The war of words between Clyde ports vying for the Arran ferry service, intensified with claims that if shifted to Troon, a new £48.5m CalMac car ferry could be delayed by a year.

But the operators of Troon harbour say this totally untrue. They could accommodate the new vessel now, as well considerably larger craft, and say it is Ardrossan that needs a massive building programme before the new ferry could dock at all.

Associated British Ports (ABP) has made a bid to relocate the service from Ardrossan to Troon. APB recently lost the P&O service to Larne in Northern Ireland and has promised to invest £8m if the Arran service is transferred to the mothballed Troon port. The new CalMac ferry is scheduled to be introduced on the route in autumn 2018.

Read more: Clyde ports' public wrangle over Arran ferry gets heated

Peel Ports operate Ardrossan Harbour, currently the mainland terminus for the ferry to Brodick, and claim that the timetable for the proposed facilities at Troon could delay completion until autumn 2019. This would leave a 12-month gap, with major uncertainty about the provision of ferry services to Arran in the interim.

In December North Ayrshire Council and Peel Ports unveiled plans to invest £13 million to secure the ferry route, but now it could be more.

Doug Coleman, Peel Ports’ project director for Ardrossan Harbour, said : “The Arran Ferry has sailed from Ardrossan for 180 years, so we have a full range of existing facilities, including a passenger terminal, adjacent railway station and car parking, which will all be upgraded as part of a £15 million investment programme if the minister’s decision goes our way.

Read more: Clyde ports' public wrangle over Arran ferry gets heated

“It will be an intensive project to construct the modern passenger and marine infrastructure necessary to accommodate the new ferry, with very tight deadlines, but if our bid is successful, we’ll definitely be ready to welcome the new ferry by the third quarter of 2018."

Joe Cullinane, leader of North Ayrshire Council, Peel Ports’ partners in the proposed redevelopment of Ardrossan Harbour described the situation as “the final nail in the coffin for Troon’s bid”.

He said: “We’ve had our planners examine this situation and they are firmly of the opinion that Troon simply would not be able to have the facilities ready in time. It wouldn’t even be close.

“In the unlikely event that Troon wins the bid, you’d have a £48.5million ferry, which has been specifically designed for the existing Ardrossan to Brodick route, sitting idle for a year as ABP tries frantically to build its terminal. It’s not a prospect that would fill anyone with confidence."

He said "an overwhelmingly convincing case" had been made to the Transport Minister, to retain the ferry "on the shortest, fastest and cheapest route" to Ardrossan.

Read more: Clyde ports' public wrangle over Arran ferry gets heated

But a spokesman for ABP said: “These claims are factually incorrect in every regard. The opposite is in fact true. Troon is ready to serve the ferry today and is already able to handle vessels considerably larger than those now under construction. The service will improve still further once the new passenger terminal is opened in 2018.

“Peel Ports are running ‘Project Fear’. We will not do that. Informed debate and true consultation are important. That’s why we’re going back to Arran next week to discuss the facts of our proposals with islanders. Getting a better deal for them and for the Scottish Government is our sole focus.”