Robert Watson-Watts

9 – Robert Watson-Watts invents radar

February, 1935

IT IS summer 1940 and with a throaty roar a squadron of Spitfires soars into the clear blue sky from an airfield in the south east of England.

The brave young pilots make for co-ordinates over the English Channel.

They already know a swarm of German bombers is on its way, intent on raining down death and destruction when it reaches Britain’s green and pleasant land.

But our airmen have an advantage.


Thanks to a brilliant Scottish scientist a chain of radar stations has been set up along the south and east coast of the country to detect enemy planes long before they appear in the skies above Britain.

But ask people if they’ve heard of Robert Watson-Watt and sadly the answer will, in many cases, be no.

Oh, they’ve heard of Winston Churchill, the great codebreaker Alan Turing and probably Field Marshal Montgomery.

But, outside of his home town of Brechin, Watson-Watt largely remains in the ‘unsung hero’ category.

To say it’s unfair that he isn’t better known is an understatement.

No Watson-Watt, no radar. No radar, no Battle of Britain victory. No Battle of Britain victory . . . no Britain?

Many historians rightly hold radar up as the deciding factor in the battle. Without it our pilots would have been flying blind.

Many Hurricanes and Spitfires would have been destroyed on the ground as attacks came out of the blue before they could get airborne.

Watson-Watt had originally conceived the use of radio waves in this way in the mid-1930s after British spies in Germany claimed the Nazis had developed a “death ray” that was capable of destroying aircraft.

In a panic the War Ministry turned to Watson-Watt to produce a feasibility study into death rays.

To everyone’s relief he dismissed the notion . . . and then produced another document entitled The Detection Of Aircraft By Radio Methods.

By the time war broke out a radar shield (it’s an acronym for Radio Detection And Ranging) had been set up.

The Chain Home network could detect high and low-flying enemy planes, and was the difference between Britain’s survival and a German invasion.

Watson-Watt was a descendant of the inventor of the steam train, James Watt.

He deserves to be ranked alongside his forefather and any of the lauded inventors of Scottish and British history – as well as the household names from the Second World War.

He is a truly great Scot and every one of us owes him a massive debt. In fact, we owe our very freedom to him.


Next time you pop a cheeky wee ready-made shepard’s pie in the microwave, say a silent thank you to Robert Watson-Watt and his team.

In the dark days of war, the scientists working on radar were trying to create airborne versions of the system so that fighters could take on German bombers at night.

The Luffewaffe had turned to attacked under the cover of darkness to devastating effect. So the team tried using shorter wavelengths – or microwaves – for greater accuracy in airborne sets.

However, creating large amounts of power at these frequencies was proving difficult.

But the 1940 invention by John Randall and Henry Boot of Birmingham University of a water-cooled cavity magnetron generated microwaves that allowed airborne radar to detect incoming enemy planes from a much greater distance.

The breakthrough had been made.

Interestingly, the magnetrons were also found to have another use – they could heat up water.

And if they could heat up water, they could heat up food!

Fast forward 75-odd years and that *ping* when your grub is ready should serve as a reminder that even the most serious of inventions can have unexpectedly handy – and tasty – side effects.