How Much Will Airstrikes On IS Cost Taxpayer?

Calculating the anticipated cost of Britain's contribution to the anti-IS coalition is imprecise at best.

According to a Ministry of Defence report to Parliament in 2010, each Tornado flight costs £35,000 per hour.

Typically, two Tornados fly each mission, lasting anywhere between four and eight hours.

So let's land somewhere in the middle: a six-hour mission costs a basic £210,000.

Then we have to consider the cost of the missiles.

The expected payload would be four Paveway bombs, £22,000 each, and two Brimstone missiles, £105,000 per unit.

So let's say that's £508,000 per aircraft in total, just a smidgen over £1m per mission.

If they carry Storm Shadows at £800,000 a pop, then the cost rises considerably.

US Navy guided-missile destroyer USS Barry launching a Tomahawk cruise missile

Tomahawk missiles, like this one being fired from a US ship, are not cheap

But then of course we should bear in mind that each aircraft might not drop its full load, so the figures distort further still.

And the Tornados need to refuel en route. Although operating costs for the Voyager aircraft aren't available, it is considerably more efficient than its VC-10 Tristar predecessor.

The TLAMs, Tomahawk Cruise Missiles, carried on the Astute class submarines, are the most expensive item - £950,000 a pop. It's unlikely many, if any, of these will be fired.

As I said, although the individual figures are accurate, the calculations are almost impossible to make, so dependent are they on mission-specific variants.

Please treat my sums with the dose of cynicism they deserve, they are merely a crude, early examination of what Britain's involvement in Iraq might cost the taxpayer.

Transporter Moves Enhanced Paveway III Bombs During Operation Ellamy

A Paveway bomb which would feature in airstrikes on IS militants

The true cost will be made available at a much later date by the MoD and National Audit Office.

One other thing I'd like to mention: it is very possible that the very RAF GR4 Tornado fast jets that take off on the first bombing missions over Iraq won't be in service by the time the mission is complete, whenever that might be.

Only three Tornado squadrons remain, next year another will disband leaving just two. They are the British military's only true ground attack aircraft, to be replaced, sometime in the next decade, by the new F35 Joint Strike Fighter.

The F-35 is a fantastic aircraft, but it is overdue, over budget and faith in it being delivered by 2020 is diminishing.

Perhaps this mission will reward the Tornado squadrons with a small extension to the life in service - and what a busy, prestigious life it has been for that aircraft.