Bomber Command was housed in a stately home that must once have been rather grand, but was now covered in ghastly green and brown camouflage paint. The WAAFs were accommodated in forty-bed wooden huts and the shift system meant the place was never free of comings and goings, day and night.

Kath and five other WAAF newcomers were told they were here ‘to observe and learn’, although what this was in preparation for was never made clear. On their first day they were led in pouring rain to a newly constructed concrete bunker called the Operations Block. Entry was through several doors in blast-proof metal and down a rough concrete stairway to a long underground corridor that smelled oppressively of stale sweat and cigarette smoke.

The map in the huge Filter Room was unlike any other Kath had seen. The North Sea, the Channel and areas of Holland, Belgium and France were filled with a spider’s web of wide arcs in a rainbow of colours, showing the coverage of RDF stations and the location of planes and ships, friendly and hostile. Here, WAAFs received reports by telephone from dozens of stations around the coast ready to be ‘filtered’ and verified against other reports before forwarding them to the Operations Rooms down the corridor. There, senior officers decided on RAF and US air force deployments, air-raid warnings, states of readiness at ack-ack gun sites, Observer Corps and barrage balloon stations.

After a couple of hours there was a change of shift, and one of the operators was asked if she could spare a few moments to speak to the new recruits.

‘Any questions?’ she asked.

‘Do you enjoy your work?’

‘Frankly, we’re too tired to think about it much. I’ve been on shift eleven hours and it’s been non-stop. Sometimes we’re following fifty tracks every minute. But I suppose it’s satisfying, knowing we’ve done our bit to help.’ She was very young, possibly only nineteen, Kath estimated, and her face was grey with exhaustion, her hair falling lankly from its bun.

‘Fifty tracks?’

‘There are hundreds, sometimes thousands, of planes and ships out there, as you’ve seen.’

‘Why aren’t there any men doing the plotting?’

She grinned. ‘They’re not quick enough. So we’ve been told.’

‘What do you do when you’re off shift?’

That mirthless laugh again. ‘Eat, wash, try to sleep.’

‘Try?’

‘Often we’re so wound up it’s almost impossible to sleep, wondering what’s happening to the planes we’ve been tracking. Especially when we know people who’re out there.’ Kath’s thoughts turned to Mark. Perhaps that was why he never told them when he was going to be ‘out there’.

‘What’s the social life like?’

‘No such thing,’ she said, shaking her head.

After ten days of ‘observation’, the new recruits were becoming restless.

‘Have I missed something? I’m still confused about why we’re here,’ one asked, after lights out.

‘Training to be filter room operators?’ someone suggested.

‘Then when does our training actually start?’