Chief Reporter

The Prime Minister gave the clearest indication yet that Britain's fleet of nuclear-armed submarines could be based in the Westcountry, in the event that Scotland votes for independence.

On a visit to the region yesterday, which took in Devonport Naval Base and the Royal Marine barracks at Stonehouse, David Cameron insisted that despite recent cuts the "Royal Navy is going to pack a huge punch in the future".

He said that Devonport dockyard "has a very secure future" while he also indicated that the Daylight Saving Bill could be resurrected – a move which would deliver massive economic benefits to Devon and Cornwall.

With Scotland due to vote whether to break away from the union, the future home of Britain's nuclear deterrent submarine fleet has become a crucial issue.

While Mr Cameron gave no indication on how quickly the submarines might have to be moved – with Plymouth the most practical destination – he was clear they would have to be transferred.

"Obviously I want Scotland to vote to stay in the United Kingdom," he said yesterday. "I will be doing everything I can to persuade the UK to stay together.

"We have to make a decision and that is why I think it is right to bring forward the referendum in Scotland and put the question so it can be determined decisively. I hope it will be a decisive yes to stay in the United Kingdom

"But obviously if Scotland wasn't in the United Kingdom, then defence facilities would have to be based within the United Kingdom, if I can put it that way."

The Scottish National Party has said Trident nuclear missiles would be removed from the Clyde under independence.

In that scenario, ministers would be forced to strike a deal with Scottish leaders allowing the Navy to go on using Coulport, where missiles and warheads are stored, and Faslane, where the subs are based, until an alternative was ready.

Plymouth would be the obvious choice, already being home to three nuclear-powered submarines, and having the only facilities capable of maintaining the current and future submarine fleet.

Mr Cameron, who chatted to Royal Marines at Stonehouse barracks before touring the submarine HMS Vigilant, which is being refitted at Devonport, painted a bright future for defence in the region.

Asked whether the dockyard would simply be left scrapping redundant submarines, after losing several ships under the Strategic Defence Review, Mr Cameron said: "I don't think that is right at all.

"We decided in the Strategic Defence Review to keep our naval bases, and to keep the Plymouth base, and I believe there is a lot of work going on here and a lot of work that will be going on here.

"If you look at the bigger picture of what is going to be happening to the Royal Navy under our defence plans, we have got the new aircraft carrier coming, we have got the Type 45 destroyers, we have got the new global combat ship coming on stream, we have got the hunter killer submarines and we have got a replacement for Trident as well.

"There is a big future programme and the Royal Navy is going to pack a huge punch in the future and a lot of that punch will be coming straight out of Plymouth.

"You should never in de fence terms put all your eggs in one basket and Plymouth I think has got a very strong and secure future."

He added: "In terms of what is happening to the Royal Navy, yes we are having to make defence savings, but at the end of that period, by 2015, we will be spending £35 billion a year. We will have the fourth largest defence budget in the world.

"I get frustrated sometimes with people who don't see that at the end of this process, at the end of the defence review, we are going to have a very, very capable Royal Navy and with Royal Marines absolutely at the heart of it."

His visit came at the end of the week which has been dominated by the Government's plans to reform the welfare system.

A series of defeats inflicted in the House of Lords were reversed by MPs despite protests from disability and poverty campaigners.

"On the welfare reforms this week I think people will be very supportive of the welfare cap," he said. "I think there is a very simple principle here that if you go out to work and do the right thing you shouldn't find that people who live on benefits but could work are better off than the average family.

"When you look at typical wages in the South West people will look at the welfare cap of £26,000, and don't forget you have got to earn £35,000 a year to have an income like that, would think that the welfare cap is quite generous, and it is absolutely right that we have brought it in.

"I was delighted that the House of Commons voted to reverse what the House of Lords had done and I think that people would be pretty amazed that Labour, supposedly the party of working people, refuses to accept that we shouldn't reform this system.

"The welfare reforms we are putting through are right for Britain, they are fair and we will make sure that the people in real need are looked after that.

"That's what our reforms of disability living allowance and employment support allowance are all about. Those who really need help will get help."