‘Phew,’ Monty said, climbing onto the platform behind him. ‘That was easier than last night.’

‘It’s a fine view in the daytime.’ Vic shielded his eyes with his hand. ‘You can see for miles. That’s Harwich, down there. That’s Landguard Fort, an old Napoleonic defence and now home of the Territorials. And up in that direction, except you can’t quite see it from this level, is Orfordness, where Watson-Watt first started his experiments.’

‘I prefer the Yorkshire hills myself,’ Monty said. ‘But Suffolk has a certain charm.’

From here you had an almost perfect aerial view of the different gardens, and for the first time Vic realised that the Round Garden was not perfectly circular but actually a slight oval, following the footprint of the old Martello tower that had once stood guard from its clifftop position.

The IFF calibrations seemed perfect but he tweaked them all the same, and they climbed down the ladder once more. ‘Let’s go back to the bunker to check this receiver’s working properly,’ he said. ‘Then I expect we’ll have to head back to Martlesham.’

In the receiver room, they waited until a few planes had flown overhead. The system was working perfectly. ‘Your Miss Motts will be reassured,’ Monty said. ‘She was very anxious when they couldn’t identify that plane acting oddly. It must have been a German doing a recce or something. Anyway, he’s probably dust by now.’

‘How did it go last night?’ Padmore asked, smoothing his luxuriant moustache.

‘There was a bit of a commotion early this morning, sir,’ Vic said. ‘They weren’t entirely sure whether the IFF was working properly, so we’ve been up the mast again this morning. It’s working perfectly now.’

‘You went up the mast yourselves? In the dark? And again this morning?’

‘Yes, sir. The engineers seemed reluctant without their manager’s say-so.’

Padmore lifted the phone and barked into it. ‘Find out which engineers were on shift last night and get them to my office. Pronto.’

He put down the phone and turned back to Vic and Monty. ‘Hmm. This leaves me with a quandary.’

There was a knock at the door.

‘Come.’

One of the engineers they’d met the previous evening entered, his face pale with terror.

‘Take a seat outside, gentlemen, would you?’ Padmore said to Vic and Monty. ‘Just for a few moments.’ Even through the heavy oak door they could hear his barks. They exchanged glances.

‘Poor bastard,’ Vic whispered.

‘Deserves it,’ Monty mouthed.

The engineer re-emerged shortly afterwards, now red-faced, and they were summoned back into the office.

‘It’s like this, chaps,’ Padmore said. ‘The only engineer who has any gumption is on leave and won’t be back till tomorrow, and I’m reluctant to risk another event like yesterday. With your permission, I’m going to ask Martlesham whether they can spare you, or even just one of you, for one more day just to make sure it’s all tickety-boo.’

Another day at Bawdsey Manor, with nothing to do except enjoy the comforts of Room Six and the officer’s mess? And perhaps the chance to find Kath?