The vapour made a corkscrew in the sky. Most of my awareness was now shut in by the binoculars and I forgot the fields and the farm buildings and concentrated on the bright fly trapped in the lens. It spiralled hypnotically. The whisper was only just audible now. I put it at close on sixty thousand feet, the Striker's operational ceiling.

A new sound came in and I rolled on to one elbow and searched for it. It was a heavy throb. Something red had started moving half a mile off, a farm tractor with a cloud of diesel gas forming above the vertical pipe. I watched it for a while and then lay back on the cold earth with the binoculars and located the plane again.

The vapour-trail had levelled off and there was a break in it. I saw or thought I saw that the machine's attitude was now horizontal. There was a lot of glare and I couldn't be certain.

I started thinking about Parkis again. The area Westheim-Pfelberg-Nohlmundt was big, something like a hundred square miles, and inside the towns that marked it there was only agricultural land. Even one of Parkis's blind swipes wouldn't be aimed at information on red tractors or abandoned ploughs. On the other hand any information about an aeroplane observed at sixty thousand feet would be a bit thin, and you didn't have to come here to see a Striker SK-6. The Luftwaffe had five hundred of them in service and you could see a squadron airborne over various sections of the map on any given day.

The binoculars in my hands were vertical and the plane was dead-centre in the lens. Immediately over the area Parkis had briefed for me there was a military aircraft performing.