I HAVE been receiving a trickle of emails over the last ten days or so complaining about the decision to close the shipbuilding yard in Portsmouth, owned and operated by the defence manufacturing giant BAE Systems, while retaining their yards in Scotland.

My correspondents perceive this not as a commercial decision by BAE Systems, but as a government conspiracy to soften up the Scots and prevent them voting for independence in their referendum next year.

This is hardly surprising since it is exactly how the BBC presented the decision. The real story is more complicated and tied up with the two aircraft carriers and other vessels on order for the Royal Navy.

We inherited a very poor deal negotiated by the last government in the contracts for the two aircraft carriers. The original cost estimates were completely unrealistic and the contract had to be renegotiated by the coalition government.

The Coalition inherited a £38bn black hole in the defence procurement budget, but the carriers are now fully budgeted within the current 10-year plan. That budget is now balanced and includes a sensible amount to cover contingencies.

Hundreds of millions of pounds in taxpayers’ money has been saved.

There was always going to be a problem when the work on the new aircraft carriers came to an end, leaving us with too much ship-building capacity and too few ships on order in the pipeline. As it is, work on the block for the second carrier will conclude before we are ready with the design for the new generation of type 26 combat ships to replace our current Royal Navy type 23 frigates.

The work-force will need to be retained and paid for during that gap. Rather than having them stand idle, we have decided to build four offshore patrol vessels for the Royal Navy.

This will cost £100m, but it will keep the yards functioning with all the skills needed for when we are ready to go ahead with the type 26 programme. Inevitably, however, once the massive job associated with building the second of the two carriers is done, there is still going to be too much capacity for the remaining work available. So, BAE systems announced that it is cutting 835 jobs in Scotland and 900 in Portsmouth (not quite the stitch-up described by so many commentators – more a sharing of the pain).

This is a harsh blow for Portsmouth. It will, however, remain the home port of the Royal Navy – with both of the new carriers based there, sustaining 11,000 jobs in the dockyards.

To keep Portsmouth’s naval port up to date there will be £100m of further investment in its facilities over the next three years. The navy is secure in Portsmouth. Slowly, but surely, we are sorting out the mess that defence was left in.

On the civilian front too, the future for Portsmouth remains bright. Last week the Government announced, almost unnoticed (only bad news carries), that Ministry of Defence land at Tipner will be handed over for an £850m planned housing development with its own motorway junction.

There is some £75m up for grabs, some of it to kickstart the Tipner development and attract private sector investment there.

Southampton will benefit too, with £7m from the regional growth fund to further develop West Quay and attract £90m in private sector investment.

It’s not all bad.