Most of the RAF planes were now in, but one had disappeared from her screen twenty miles from the coast. Sending the urgent alert, she visualised the air crew scrambling out of their sinking plane, perhaps looking around for the others, praying that they all managed to get into their dinghy and that air-sea rescue was able to find them.

She turned back to the hostile blip, now estimating seventy-five-plus aircraft, apparently heading straight towards Suffolk. How vulnerable we are, Kath thought, so visible and right on the edge of the coast. The plotter at the table at the other end of the room said grimly, ‘Been nice knowing you, girls.’ But there was no time for being scared. She took two more plots. The blip was fading, indicating that they had veered south-east, probably heading for London. The information went through to Stanmore.

Soon enough, RAF fighter crews would be scrambling from their beds, running across darkened fields and into their planes; ack-ack teams would be getting their range, and Londoners would be wearily making their way into air-raid shelters and underground stations, facing yet another disturbed night ahead.

Turning quickly back to the ‘tube’ screen, Kath detected a new blip at three miles heading away from land: two aircraft, or possibly three. The double V showed they were friendly. At eighteen and twenty miles out they began stooging around, back and forth, round and round. Must be the air-sea rescue looking for the ditched crew.

Her eyes were burning. Two hours was quite long enough to focus on that fuzzy screen, and it was time to swap places. She moved across to work at the plotting table and then, at the next swap, to take her turn as ‘teller’, passing information through to Stanmore on the telephone. She imagined the frantic WAAFs at Stanmore, rushing between phone and table, the hubbub of shouted instructions, the serious faces of the top brass observing from the balcony above as the raid headed for London, and prayed that Mark was not already in the fray.

And so the night went on. At first light their screens burst into life, filled with large blips all moving towards Belgium and Holland. ‘It’s the Yanks,’ someone said: the USAF taking off from their new airstrips, en route for Germany’s war installations. The screen was soon a solid mass of blips from zero to thirty miles.

‘That’ll be a sight for sore eyes,’ the shift supervisor said. ‘Take it in turns to take a quick dekko.’

It was the noise that struck them first, the persistent roar of low-flying heavy aircraft. But the sky was empty. Then, from the west, came hundreds of them in great ordered flocks, filling the sky as far as the eye could see, some low, some higher up; and now, as they watched, starting to pass over the coastline and heading out towards the continent. It was an impressive sight, enough to make your heart race. Was Mark up there, heading out on what would undoubtedly be a dangerous mission? Was he looking down on his home town and wondering when, or whether, he would ever get back here? Kath’s eyes filled with tears, her thoughts in a turmoil of pride and terror.