my knickers round my ankles.’
‘Quiet!’ shouted Sitwell.
Kay sat with her pencil poised above her notepad. A few seconds passed. The corporal was listening intently. He had his hand held up, like a marshal with a flag at the start of a race. ‘Contact bearing two six zero; altitude thirty-one thousand; velocity three two four seven feet per second … Contact bearing two six zero, altitude thirty-nine thousand, velocity three eight six two …’
‘There she goes,’ muttered Knowsley.
‘… Contact bearing two six zero, altitude fifty-seven thousand, velocity four zero three eight …’
‘My God, the speed of her …’
Sitwell said, ‘Has anyone got the positions for the y-axis yet?’
One of the WAAF sergeants was writing rapidly. ‘Yes, ma’am.’
The corporal announced, ‘Contact lost.’
‘She’s already out of range,’ said Knowsley. ‘Well!’ He shook his head and let out his breath. ‘Now we wait.’
One of the sergeants sat with the phone tucked under her chin, on an open line to Stanmore, a pencil in her hand. Another stood by the large-scale map of London and south-east England holding a tin of pins.
The room fell silent again. Minutes passed. It was sinister to contemplate the rocket soaring towards space, Kay thought, the curve of its flight path flattening, the gradual turn, the speed of its descent. There will be someone on the ground in London just like I was, someone going about their life on a normal Tuesday morning, full of plans and trivial concerns, entirely unaware that the mathematics of the parabolic curve have already condemned them. She looked down at her sheet of paper – at the pencilled figures representing the values of bearing, height, speed and position. The integers of death. She remembered how she had just pulled her dress over her head in Warwick Court when something changed in the atmosphere, as if the air had been sucked away, and then came the crack of the sonic boom, the express-train roar of the incoming rocket, all of it swallowed by the rumble of the collapsing building.
‘Report of impact,’ called the WAAF sergeant with the phone. Her voice pulled Kay back to the present. Another pause, while the radar operators in Home Defence in England made their calculations. ‘Latitude bearing fifty-one point thirty, three one point six one four six. Longitude zero, zero, thirty-seven point eight seven nine two.’
The sergeant put a red pin in the map. Kay picked up her slide rule. All thoughts of what was happening in London evaporated. She was surprised at her own calmness. Her mind bifurcated, one part concentrating on the procedure that had to be followed, the other making sure her calculations were accurate. The window on the slide rule moved back and forth, comforting in its precision. The world reduced to numbers. After exactly six minutes, she raised her hand and passed her notebook across the table to Barbara. Knowsley and Sitwell gathered at Barbara’s shoulder to watch her check Kay’s calculations against her own. Kay studied their faces. Now she was nervous. She would have liked a cigarette. After a minute, Sitwell took the notebook over to the map that showed London and the North Sea all the way to the Dutch coast. She measured off the distance.
‘Latitude bearing fifty-two point seven, four point two seven zero two. Longitude four point one seven, fifty-two point three zero nine eight.’
‘Latitude bearing fifty-two point seven …’ One of the WAAF sergeants, in the polished accent of a BBC announcer, repeated the coordinates clearly and calmly down the line to Fighter Command.
Barbara smiled across the table at Kay. ‘Don’t worry, sweetie, you got it bang right.’
At RAF Coltishall, nine miles north of Norwich, four Spitfire pilots – members of 602 (City of Glasgow) Squadron – who had been sitting in their cockpits for several hours, were ordered to scramble. Their warplanes were brand-new Type XVIs, only received from the factory that month, specially modified to serve as bombers. For several days the squadron had been studying high-altitude reconnaissance photographs of The Hague, familiarising themselves with the Type XVIs and practising dive-bombing. Straining under the weight of two 250-pound bombs, one under either wing, they roared down the runway and took off into low cloud. Flying in tight formation, they turned east, crossed the long sandy beach between Waxham and Winterton-on-Sea and headed over the North Sea towards the Dutch coast, 120 miles away. The attack coordinates were radioed to them by the control tower. At a maximum speed of just over 300 mph, they would reach their