(MENAFN- The Conversation) The collapse of the prosecutions of Christopher Cash and Christopher Berry is a reminder that bringing charges for espionage can be an extremely risky business, particularly in western democracies. Cash and Berry were accused of spying for China, but the CPS dropped the case before it could go to trial. They deny the charges against them.

Read more: How Britain's weakened global position may have pulled it into a Chinese spying scandal

Espionage cases have caused headaches for UK governments for decades. Harold Macmillan, who as prime minister from 1957 to 1963 suffered more than his fair share of embarrassment from them, complained to his biographer:“You can't just shoot a spy as you did in the war.”

Instead, there would be a“great public trial”, during which“the Security Services will not be praised for how efficient they are but blamed for how hopeless they are. There will be an enquiry... a terrible row in the press, there will be a debate in the House of Commons and the Government will probably fall.”

Macmillan was describing the case of John Vassall, whose 1962 conviction for spying caused a major political scandal. But his words resonate powerfully today.

Espionage trials risk revealing the sometimes highly confidential methods by which evidence had been gathered against the accused. And in some cases, the evidence itself is too circumstantial to prove guilt beyond reasonable doubt.

One of the major postwar sources of secret information about Moscow's agents were the Venona documents. These were Soviet messages partially decrypted by US intelligence officers. But the Venona project remained a closely guarded secret until the 1980s, and only officially made public in 1995. As such, it proved necessary to obtain other forms of evidence to convict some of those incriminated by this source.

In the case of Julius and Ethel Rosenberg, accused of passing nuclear secrets to the USSR, this took the form of a confession by Ethel's brother, David Greenglass. Nevertheless, the couple's execution in the US in 1953 drew condemnation from across the world, and Ethel's conviction remains controversial.

It was only possible for British courts to convict another nuclear spy identified by Venona, Klaus Fuchs, because patient interrogation by MI5 officer William Skardon eventually led him to confess.

Immunity or prosecution

The current MI5 chief, Ken McCallum, has publicly distanced himself from the collapse of the cases against Cash and Berry, and the Security Service clearly hopes that the 2023 National Security Act will make future prosecutions much easier. But historically, the Security Service has sometimes been more than happy for suspects to avoid a trial in return for cooperation.

In 1961, MI6 officer George Blake was convicted of espionage for the USSR under section one of the 1911 Official Secrets Act. However, concerns over the weakness of the evidence against him led to questions about whether the case could or should be brought to court.

The authorised history of MI5, (2009) revealed that intelligence chiefs were prepared to contemplate offering Blake immunity from prosecution, in return for a confession. Luckily for them, he confessed before any such offer was made. He was sentenced to 42 years in prison, but managed to escape in 1966 with the help of two peace campaigners. He lived the rest of his life in Moscow.

Two decades later, similar concerns surrounded the case of Michael Bettaney, a disillusioned MI5 officer suspected of passing secrets to the USSR. As they interrogated Bettaney, his colleagues were anxiously aware that they did not have enough evidence against him that could be used in court. Potentially, he could simply walk away and even leave the country. Again, luckily, Bettaney broke under questioning, confessed and was sent to prison.

Political headaches

Aside from questions of evidence, the British establishment traditionally shied away from anything – criminal trials included – that cast light on the secret world of intelligence gathering.

Writing in 1985, military historian Michael Howard likened the prevailing attitude to that towards intramarital sex:“Everyone knows it goes on and is quite content that it should, but to speak, write or ask questions about it is regarded as extremely bad form.”

When the subjects of sex and espionage merged, as they did explosively in 1963 with allegations that the war minister John Profumo had shared a mistress with a Russian spy, they created a political shock which left Macmillan's administration mortally damaged.

Christine Keeler, right and friend Mandy Rice-Davies, key figures in the Profumo affair. Alamy/Associated Press

The following year, it became clear to the intelligence community that Anthony Blunt, the surveyor of the queen's pictures in the royal household, was the“fourth man” in the Cambridge Five spy ring. The Tory government of Alec Douglas-Home gladly accepted the advice of the heads of MI5 and MI6 that Blunt should be offered immunity from prosecution in return for his full confession, and his treachery concealed from the British public.

The arrangement spared Douglas-Home a scandal on the scale of Profumo. But after the public unmasking of Blunt in 1979, the embarrassing task of defending the offer of immunity was left to Margaret Thatcher.

Frequently in the past, the urge to punish spies has been subordinated to broader considerations of the national interest. Much comment in the case of Cash and Berry has focused on the supposed difficulties in defining China as an“enemy”. However, the easy cold war distinction between enemies and allies has been breaking down.

The British government now regularly finds itself having to maintain effective diplomatic and trading relationships with countries that are disagreeable or positively malign. There is much about the current case we do not know and may never know. But if it turned out that influential figures in the British government were reluctant to endanger relations with China in the interests of prosecuting two fairly low-grade alleged Chinese agents, I doubt whether anyone would be very surprised.

Want more politics coverage from academic experts? Every week, we bring you informed analysis of developments in government and fact check the claims being made.
Sign up for our weekly politics newsletter, delivered every Friday.

MENAFN20102025000199003603ID1110222076