WITH a packed timetable of lessons and games, it’s more nine-to-five than MI5 these days for pupils at Abingdon School.

But 60 years ago there was one pupil whose Italian family broke that mould.

When Gil Pontecorvo failed to make it back to classes for the first day of term on September 19, 1950, teachers assumed car trouble had delayed the Pontecorvo family holiday in Italy. But at the same time alarms bells were ringing in British intelligence agencies.

Gil’s dad – Dr Bruno Pontecorvo, a senior scientist at the secret atomic research establishment at Harwell – was missing.

And his disappearance came only eight months on from a confession by another Harwell scientist, Klaus Fuchs, that he had been passing atomic secrets to the Russians during the Cold War.

The UK’s top secret agents were tasked with finding out if Dr Bruno Pontecorvo was another spy.

It wasn’t until five years later that Dr Pontecorvo surfaced in Moscow and announced he had defected to the Russians.

Now, 64 years down the line another senior scientist believes he has discovered the truth about what happened.

Frank Close, former physics professor at Oxford University, former head of theoretical physics at the Rutherford Appleton Laboratory, and the 2013 winner of the Royal Society Michael Faraday Prize for excellence in communicating science, is unveiling his discoveries in a book to be published next October.

His biography of Dr Pontecorvo, A Life of Two Halves, is the culmination of more than three years of research.

Prof Close said: “Having seen previously unobtainable papers from the MI5 archives, I now know why Bruno Pontecorvo fled so suddenly.

“And last week, for the first time, I saw his secret logbooks which reveal what he did in the USSR.

“The full story will come out in my book next year, but some tasters will be given in my talk at Abingdon School.”

Scientists and historians have continued to debate if Dr Pontecorvo did indeed spy and pass on information.

Prof Close met Gil, who is now a Russian nuclear physicist, and interviewed his family. He also examined previously closed files from both the West and the former USSR.

Prof Close is visiting Abingdon School on Wednesday for a talk to describe the trail he has followed, the crucial documents he has examined.

The free lecture starts in the Amey Theatre at Abingdon School in Park Road from 7.30pm.