@Alan Firminger
"In the late sixties Nimrod was being developed as airborne early warning and tales were released that it was being abandoned because it saw traffic on German autobahn."
This wasn't a tale, it was true, and it wasn't the 60's, it was either the 70's or 80's.
They developed a fancy new radar for the Nimrod and they discovered it was picking up quite successfully vehicles moving along the roads.
So with all this additional clutter, they commenced development of further processors to try to remove that clutter.
I have forgotten who the prime contractors were, possible GEC and Marconi; in those days the MoD (PE) dished out most of its contracts in the form of what was called "cost plus" contracts, which I suppose today would be called Time and Materials.
The projects in particular the Nimrod AEW project was a cost plus, it wasn't a fixed price contract, and the project dragged on for years and years. It wasn't delivering, but the costs just keep mounting up. The technological achievements were great, but eventually the government decided enough was enough and terminated it.
If I recall correctly, the two prime contractors blamed each other, and cited poor information sharing between the two companies, claiming that each company couldn't share information because the information any one particular company had, was secret.
The whole thing was a long running farce.
For years later, the Nimrod AEW aircraft that had been converted, were just left lying around, including one at RAF Finningley, if I remember!
The project was abandoned and this led to the RAF/MoD leasing the Boeing 737 AEW aircraft from the USA, which are still in use today by the RAF.
It was a contraversial decision, people wanted the UK to develop a UK aircraft with newer more advanced technology, and in particular newer computing/processing technology, but the Boeing 737 was a larger aircraft and had more space inside.