Robert Watson-Watt was a great inventor who made a major contribution to victory in the Second World War with the invention of radar, but he was also Scottish.

His eureka moment did not involve water spilling out of a bath or one portion of his five-a-day falling on his head; it involved beer.

It is one of the less well known facts of history: beer defeated the Nazis.

The eureka moment came as Watson-Watt finished swigging from a bottle of beer and threw it away into the grass (he helped save us from the Nazis, but he didn't contribute to a tidier Britain).

As he watched the bottle bounce away, he realised he could do something similar with radar waves: he could bounce them off the ionosphere and back to receiving stations, thereby giving the British more warning of approaching German planes.

That this story, and the story of Watson-Watt's life and work, is not better known is sad, although he is by no means the only neglected Scottish inventor (James Clerk Maxwell being the other obvious one). And at least the BBC is raising Watson-Watt's profile with its documentary/drama Castles In The Sky (BBC Two, Thursday, 9pm), which followed the inventor and meteorologist from his eureka moment through to the first moments of the Battle Of Britain.

Watson-Watt, who was from Brechin, Angus, was played by Eddie Izzard with a lovable generic Scottish accent and an amiable clumsiness, but he also brought out the inventor's sharpness.

When he first came up with his idea, Watson-Watt was met with snobbery, pessimism, bureaucracy and some of the other less likeable traits of the British psyche, but he narrowed his eyes, kept his focus and got on with it.

He also won over his most important ally: Winston Churchill. "Go and build your castles in the sky," said the PM.

Watson-Watt then went off to his workshop with his team, including his most important collaborator, Arnold Wilkins, and the drama that unfolded was a bizarre mix of the histrionic and the pedestrian.

"We must build a death ray!" said one of the scientists, only for a long section of the film to focus on what size of valves to use.

"We'll have to build smaller valves!" said Watson-Watt, which is never going to be a dramatic line however hard you say it.

It was great geeky drama though, full of serendipity and a delight in detail.

It was also a recognition of the disturbing but inspiring fact that war has always been a great spur to invention but also a great dismantler of division.

Watson-Watt did not wear the old school tie, he was not seen as the right sort, and he had a funny accent, but none of that matters when you are saving lives.