just been cleared of Germans. Because of its position, and the lack of hills, it gives us a perfect side-on view of the missile’s trajectory. These new radars have cathode-ray direction-finding displays, so not only can we pick up the rockets once they reach an altitude of about thirty thousand feet, we can also record their flight path before they pass out of range.’
‘And that helps us, does it?’
‘It could do, sir. When this all started, we rather hoped the V2 would turn out to be guided by radio signals, which we might at least have been able to jam. The Germans obviously anticipated that. They don’t use radio guidance. We believe the missile to be purely ballistic – that is to say, the engine shuts off and it follows a perfect arc, similar to if one throws a cricket ball from the outfield. And that is a potential weakness we might be able to exploit.’
He broke off, obviously unused to speaking at such length. The air commodore made an encouraging gesture. ‘Go on.’
‘Well, a ballistic arc is mathematically calculable. If we have data giving us the missile’s trajectory at the moment it becomes ballistic, and if we have the precise point of impact, then it should be possible, in theory, to work backwards and calculate the spot on the boundary from which the cricket ball, so to speak, was thrown.’
The officers looked at each other. Templeton sat forward in his chair. ‘That’s quite an interesting notion. The question is: can we exploit it operationally?’
‘Obviously we’ve been thinking hard about that. Essentially, it becomes a race against time to put the two halves of the data together. The first half, from the MRUs in Belgium, can start to be collated on site a minute or two after launch. The second half can be supplied from Stanmore as soon as Home Defence radar gives us the point of impact – that’s about three minutes later. So for the sake of speed, the calculating needs to be done as close to the mobile radars as possible.’ He turned to the officer from Fighter Command operations. ‘How long does it take to get a Spitfire off the runway at Coltishall and over the Dutch coast? Twenty-five minutes?’
‘About that. Give or take.’
‘So if the planes are scrambled as soon as a missile launches, and the point of impact is reported to Belgium as soon as the V2 hits, we’d have about twenty minutes to make the calculation, locate the rough area of the launch site and get the coordinates radioed to the pilots while they’re over the North Sea. In theory, we could bomb the target, say, thirty-five to forty minutes after launching, while there are still men and vehicles on site.’
Templeton turned to his aide. ‘Did you get all that?’
The flight lieutenant was still writing. ‘Yes, sir.’
‘What does everyone think? Is it feasible?’
With varying degrees of enthusiasm, the officers agreed it was.
Templeton said, ‘It gives us a chance, at least. And in the absence of any other options, it’s certainly worth a try. Good. Let’s start tomorrow.’
Knowsley looked alarmed. ‘I’m not sure we can start as soon as that, sir.’
‘Why not? You said yourself we have the radar units in place. And we have 303 Squadron at Coltishall. The pilots are familiar with that area of Holland.’
‘We still need the personnel in Belgium to make the calculations.’
‘Are the calculations difficult?’
‘It’s fairly sophisticated algebra. It requires an ability to use a slide rule, for a start. I’ve pulled a few girls out of the Filter Room and started training them – with somewhat mixed results, I have to admit.’
‘How many do you need?’
‘For round-the-clock coverage, to begin with, at least eight.’
‘Come on, Wing Commander! There are a hundred and eighty thousand WAAFs in the country! It has to be possible to rustle up eight capable of using a slide rule by tomorrow, surely?’
Knowsley was more stubborn than he looked. ‘It’s a demanding job, sir – working under extreme time pressure, putting pilots’ lives at risk, without any room to make an error.’
Templeton said, ‘I don’t care how you do it, but I intend to go to my office straight away and telephone the Secretary of State to tell him that we have finally come up with a plan that might just work, and that we’ll have eight WAAFs on a plane to Belgium tomorrow. Is that clear?’
If Knowsley was minded to debate the issue further, he clearly thought better of it. ‘Yes, sir.’
‘Good. I’ll