Doris said softly, 'I can't hear much engine noise, can you? Maybe we'll get away with it tonight. I'll need to go back out in a minute, check that everybody is where they should be. We've got lists we have to tick off, or we get stick from the officers. But maybe tonight-'

There was a wallop, like a great fist slamming down. The ancient vault shuddered, and bits of dust and brickwork hailed from the roof. Suddenly the place was alive with noise, kids screaming, somebody with a splash of blood-red on his forehead calling for help. Doris clung to Mary's hand, suddenly scared; Mary put her arm around her.

There was another wallop, even more violent, and the lights flickered and died.

14 September

Hilda Tanner found Ben Kamen just where his Home Guard commander said he would be, out in the country a couple of miles or so north of Hastings, digging holes in the ground with a gang of other men.

She parked her car and walked through a field of corn stubble. It was a fine, bright Saturday afternoon, with just a hint of autumn coolness in the air. The field was cluttered with broken-down tractors and other vehicles, and loops of wire big enough for Hilda to have stepped through.

In the distance to the south above Hastings, an aerial battle was in progress. Hilda felt like a veteran of the air war, for the radar stations, including her own, had been getting a pasting. She recognised the way the Messerschmitt 109s were flying, in their 'schwarms' of four aircraft, and the Stuka bombers diving down onto their targets like predatory birds. The guns on the ground were firing back, releasing balls of fire that lanced up towards the planes. A big pall of smoke rose up from the ground, beyond her horizon. Perhaps one of the planes had gone down. The sky was full of smoke and colour; the Messerschmitts' tracer bullets were bright yellow and green.

It was an astounding sight when you stopped to think about it. But the workers in the field didn't even look up. Such spectacles had filled the sky around the towns and ports and airfields of southern England for a month now. There had been one day of relief, when the Luftwaffe had launched a massive raid on London: the Saturday Blitz, the papers had called it, Saturday 7 September. Everybody had hoped, shamefully unless you were in London itself, that the Germans were changing tactics, that they had abandoned the idea of winning the aerial war and were resorting to terror against civilians. But then the usual pattern had resumed, as the Luftwaffe had pursued its objective of knocking the RAF out of the war through sheer attrition.

Hilda approached the work party. Ben was working alongside an older man of maybe fifty. The other Home Guard men leaned on their shovels and wolf-whistled and larked about, showing off their puny muscles, calling in their ripe Sussex accents, 'Oi, WAAF! That uniform fits you pretty nice.' 'Hey, WAAF, what's he got that I haven't got?' 'Tell you what he hasn't got. A bit of skin on the end of his knob…'

She acknowledged it all with a tight grin and kept walking. The older man waved them silent. 'Stop drooling, you lot.' He had a faint Irish burr, and big hands, a farmer's hands, the biggest hands Hilda had ever seen.

Ben stuck his spade in the ground, wiped his hands on his trousers, and faced Hilda. 'It's lovely to see you. You came all the way out here for me?'

'Well, I've got a couple of messages for you.'

He asked intently, 'From Mary Wooler?'

'Yes, and from Gary too. Me and Gary actually.' She held herself straight, and hoped she wasn't blushing.

'Well, well. Look, I'd give you a hug if I wasn't sweating like a good'un. Tom, do you mind?'

'You take a break, don't mind me.' Tom continued to scrape at the ground.

Ben took his jacket from a heap of stakes, spread it on the ground and gestured for Hilda to sit. He squatted easily on the ground himself. He took a swig from a milk bottle full of water, and offered it to Hilda; she refused.

'Fun, is it, digging holes in the ground?'

'Oh, the glamour,' Ben said. 'But you know the theory. We're just trying to muck up every field and open space to stop planes and gliders landing.'

'It's no ruddy fun,' Tom growled. 'The ground's baked hard as concrete. You can see what we're up to, though.' He pointed to a row of completed installations; they were simple tripods of scaffolding, like the frames of teepees. 'I grow my peas and beans up poles set like that.'

Hilda called, 'Wouldn't you rather be digging your garden – um, Tom?'

'Given half a chance,' he said with a grin. 'But I'll tell you what, sooner this than route marching. First time we went marching, our Home Guard platoon, a quarter of a century just fell away in a flash. I'll swear I could smell the cordite and the mud. I was in Flanders, see. Never thought I'd be back marching again, not in my lifetime. Well, well.' He sighed, and continued to ram his spade into the reluctant ground.

'Tom's been a good mate,' Ben said. 'Keeps the other lads off a bit.'

'Give you a hard time, do they?'

'Nothing I can't handle. Funny, though, they bait me for being a German and a Jew.'

'But sooner here than that internment camp, from what Gary told me from your letters.'

'Oh, yes.' In late June Ben Kamen's name had come up on a list of potentially enemy aliens. While waiting for his tribunal, he had been taken off to an internment camp in Liverpool. 'It was a half-finished council estate in a place called Huyton. What a hole. But the tribunal eventually classed me as a C.' Category A were considered hostile to the war effort; B were for some reason doubtful; C were friendly and no threat. 'But even then, when I joined the Home Guard, they kept me away from the guns and handed me a shovel instead. Funny, that.'

'Well, it's behind you now.'

'I hope so,' he said fervently. 'How's your war? I think I expected to see you up there by now.' He glanced at the sky. 'In a Spit or a Hurricane. I hear they are planning to send women to the front line.'

'So they are, but I've no training. I'm working at an observation station on the coast.' She had picked up the habit of not using the word 'radar' unless it was necessary.

He looked at her. 'It's coming, isn't it?'

'What?'

'The invasion.'

'Why do you say that?'

'Just looking around. Piecing bits together. I mean, the work we've been doing, you can see the logic.' He mimed an enclosure with his hands. 'You have this crust around the coast – tank blocks, barbed wire, ditches, mines. Then further back we've been building what they call the stop lines. Natural barriers like rivers and canals and forests, but reinforced with tank traps and pillboxes. Defence in depth. You can see it taking shape.'

'I don't think they'll come,' Hilda said. 'For one thing they haven't been able to knock out the RAF. Those Me109s of theirs are too short-range. The Hurricanes and Spits can always retreat to fields in the north of England. The Luftwaffe can't win.' That was the official line. But, Hilda had heard it said at work, all the Germans actually needed to do was to beat the RAF back from the skies of southern England, and achieve 'local air superiority'. And Hilda knew from her own experience that if they kept battering at the airfields and radar stations and sector stations of the south-east, the delicate system of command and control behind the RAF's operations could soon crumble. It would actually be better for Britain's prospects in the war if the Luftwaffe turned on London again. But she said firmly: 'No, they won't come. And all your digging will be for nothing!'

'So where's Gary now?'

'Well, he's recovered. He's been reposted, a lot of the BEF veterans have. Now he's to be with an international unit in the Twenty-ninth Brigade. He's due to join it on Friday.' She hesitated. 'They're stationed north of Eastbourne. I was hoping he'd be sent to the Twenty-first. A lot of the veterans are with them, north of London.'