Clyde shipyard bosses revealed they are within weeks of signing an agreement that could see a new generation of frigates being built at Govan and Scotstoun.

Clyde shipyard bosses revealed they are within weeks of signing an agreement that could see a new generation of frigates being built at Govan and Scotstoun.

They are expected to win a share of work on up to 18 new ships to replace the Type 22 and Type 23 ships currently in service with the Royal Navy.

Alan Johnston, chief executive of the yards' owners BVT Surface Fleet, revealed the signing of the terms of business agreement between the company and the Ministry of Defence would seal a 15-year commitment guaranteeing defence work for the Clyde.

It's a boost for the yards after a week in which a leaked company document outlined plans to reduced warship building in the UK to one location - either the Clyde or Portsmouth - raising fears of thousands of redundancies and a £1bn rise in the cost of two new aircraft carriers being built for the Royal Navy.

However, the scale of the new work is unknown and there is no guarantee that all 3500 workers at the Clyde yards would keep their jobs.

Mr Johnston said he expected steel cutting for the frigates could start in 2013, a critical point for the yards because work on the giant aircraft carriers that currently fill the order books will be far advanced.

Steel cutting starts at Govan on Tuesday and the first of them, HMS Queen Elizabeth, is due to be in service in 2016 with HMS Prince of Wales following in 2018.

While the frigates are potentially good news for the Clyde, Mr Johnston offered no guarantees whether it would be chosen ahead of Portsmouth.

Asked if the steel-cutting for the new ships would start at Govan, he said: "I would suspect that's a prospect, yes."

But he added: "We have not decided; we have to look at our assets nearer the time."

Two ships on which work was started in Portsmouth are now being completed at Scotstoun, a factor which Mr Johnston said demonstrated BVT's ability "to flex our resources across the UK".

He said he was also looking for export opportunities with customers and partners "who could team with the Royal Navy" to share design costs and procurement acquisitions.

He warned that the international defence business was "quite difficult to predict" but added: "I think for the first time in a long time this industry can be confident that we do have a strong opportunity to export."

Mr Johnston, who was the author of the documents that had been leaked, insisted they were an example of "the worst case scenario planning" carried out by all prudent firms.

He said: "We are looking at planning scenarios on the downside, but our aim is to drive the upside of this business and we see a very solid future here on the Clyde."

Despite his upbeat message, he was cautious about what would happen as work on the carriers wound down.

He said: "In terms of guaranteeing employment after seven years, I would be a very foolish chief executive to stand here and say I am guaranteeing work forever."

Mr Johnston was speaking at Scotstoun, where he was accompanied by Scottish Secretary Jim Murphy, who cleared his diary to meet the unions and management after the furore caused by the leaked memo.

Mr Murphy said: "Our message as a Labour government, trade unions and management is that the Clyde has a remarkable history in shipbuilding, but it also has a big future."

He denied that ministers had been involved in agreeing the section of the leaked memo which revealed the MoD had committed to underwrite the costs of closing one of BVT's yards.

"I spoke to MoD ministers and no MoD minister has agreed to redundancy payments because that is not the business we are in," he said.

"It's about bringing jobs here, not about making people redundant, and the unions know that."

After the visit, Jamie Webster, the GMB convener at Govan, said: "We know that post-carrier there is a downturn in the navy's requirements. That will pose questions for us but they're not unanswerable - whatever work the navy has we want for the Clyde."

John Dolan, GMB convener at Scotstoun, added: "At this stage, we have a huge future. We have no problems with the company or the government about the future of shipbuilding on the Clyde."

Deputy First Minister and Govan MSP Nicola Sturgeon said Mr Murphy had to deliver more than a "photo shoot" for the workers.

"It is all very well seeking assurances from BVT but Jim Murphy must deliver a guarantee from Gordon Brown that the Ministry of Defence will not force the closure of any Scottish shipyard," she said.