My Father Eric, Nuclear Spy

The University of Vienna has hosted an unlikely book launch, recalling the long-hidden exploits of one its former star professors.

Scientist Spies, by Paul Broda, explores how both the author's father Engelbert, code-named Eric, and his stepfather Alan Nunn May, passed on British state secrets to Russia free of charge.

The material was so useful that the Soviets were able to speed up their own nuclear programme, pipping the UK to the post with their first nuclear bomb tests in 1949.

Engelbert Broda, who won a PhD in Vienna in 1934, but emigrated to the United Kingdom in 1938, was effectively outed as a spy in 2009, through evidence compiled by a Russian journalist who had been able to access previously classified files.

However, by then, the professor was already pushing up the daisies in an avenue of merit at a the famed Viennese necropolis of Zentralfriedhof.

During the war, Broda had worked at Britain's Cavendish Nuclear Laboratory. However, unbeknownst to his employers, he was handing on state secrets to Moscow.

In 1943, KGB officers filed a report noting that Eric was "the main source of info on work being done on Enormous [the codeword for nuclear bombs], both in England and the USA".

So suspicious were the Americans about leaks that they stopped passing on information to their British allies.

In 1947, Broda returned to his native Vienna. One of his British colleagues, Alan Nunn May, had been imprisoned the year before for handing on material to Moscow.

After the latter was released in 1956, he married Broda's ex-wife Hilde, the mother of the author of Scientist Spies.

Paul Broda attempts to paint an open-minded picture of his family, highlighting his father's opposition to Nazism in 1930s Vienna.

As the book's original publishers note, he describes his parents as principled and committed individuals who believed that they were making the world a safer place, but invites readers to form their own views.