And yes, that makes it more expensive as well.

There's a job title called requirements managers, which means the person who is deciding on behalf of the Army or the Navy or the Air Force what the specification for the equipment should be.

And those people rotate through their job every two years.

And the new person coming in will both won't know as much as the person who just left, but also will want to leave their mark on a programme.

And so, you know, one of my slightly less tasteful jokes is that requirements managers are to programs as dogs are to lampposts.

And they want to leave their mark to prove that they were there.

And so they will change a program.

That means the contractors would be liable for any cost overruns.

Sir Bernard Gray, a former top Ministry of Defence official,

So it's not our part of the ship, but if we can't run the gas stations, that's about 50% of installed capacity.

And the problem is, as you say, at this time of year, we're probably above 50% requirement and peak time for that is tea time.

And the worry is that the grid will then have to be shut down rather than fall over.

So you have to manage ways to keep hospitals and things going.

So probably we're losing electric power to a large part of the civilian population.

I mean, they might cycle it through over three-hour time blocks or something, but broadly speaking, you can't run the whole grid.

Bernard Gray is referring to a defence industry site in Lancashire.

What Tom's saying is that a submarine is the best way to strike back against Russia, and they should aim to take out one or more of the Russian submarines.

It's helpful that the one that we've seen is next door to Lossiemouth.

Both Tom and Bernard want to target the Russian submarine that chose to surface off the Scottish coast the previous day next to a passenger ferry.

And therefore, from that point of view, I would be prosecuting the area with as much of P-8 as we've got.

Just bearing in mind it's the P-8 base, our quickest remedy for the Prime Minister's point of view is finding and prosecuting.

We know it's an SSN, we know where it is, and we've got all of our ASW aircraft within 50 miles.