The government's decision last summer to build two new super aircraft carriers, one pictured above, has effectively secured the future of Portsmouth Naval Base.

And a merger of two businesses to create one single defence corporation will boost opportunities at the base, bringing in shipbuilding from across the globe.

Shipbuilders VT and BAE are set to embark on a joint venture to build the aircraft carriers and as part of the contract, other major MoD projects will go to the Portsmouth-based partnership.

The two firms have a framework agreement to merge their shipbuilding and naval support, bringing two yards in Glasgow and our naval base under the one management force in Portsmouth.

VT spokesman Phil Rood said: 'It makes sense because we already work quite closely together and we're the only remaining naval ship builders in the UK.

'The joint venture will create a world class shipbuilding and naval support entity.'

The carriers will be the biggest and most powerful surface warships built for the Royal Navy.

VT will own 45 per cent of the new venture which will assume responsibility for building the carriers in sections in Glasgow, Barrow and Rosyth, with part of the hull built in Portsmouth.

The venture will include a terms of business agreement guaranteeing the partnership all the design, construction and support of major MoD projects over the next 15 years.

But the merger is under a cloud of uncertainty as while the government conducts a review of all defence spending projects, it cannot give the green light.

So, while waiting for the nod, the two firms have prepared by boosting trainee levels, and working on other projects.

VT has recruited more than 100 new workers over the past six months and a further 50 are set to be recruited in the next month.

That will bring the overall strength of the workforce up to 7,000, many of whom will be working on the carrier projects.

Mr Rood said: 'The go-ahead for the joint venture being formed rests on the government giving a start date for the manufacturing.

'Until that issue is resolved and the defence spending budget is sorted out it would seem unlikely that the go-ahead will be given.

'But we're encouraged by the fact the government has ordered equipment, including 80,000 tons of steel, and the Prime Minister is committed to building the ships.

'The ships will be built but the clarification of the timing is where the uncertainty lies.'

When the thumbs-up finally comes, VT will hold an extraordinary general meeting to get approval from its shareholders for the merger. In the meantime, Portsmouth workforce is getting on with orders for ships from Oman and Trinidad and Tobago.

When the carriers project is under way the venture will have a turnover of around £1bn a year.

But it's not yet known whether the partnership has long-term prospects or whether the two firms will go their separate ways once the carriers, the HMS Queen Elizabeth and HMS Prince Of Wales, have sailed in 2014 and 2016 – or even before.

Mr Rood said: 'We've made no secret that in the long term VT will become more focused as a support services business, which means within the agreement there's provision for VT to exit the shipbuilding joint venture. At what point we do so, if indeed we do, has yet to be decided.'