The latest release of MI5 files to the National Archives is reported in some of this morning’s UK papers (12th April 2017) and in a good blog on the National Archives website by Dr Richard Dunley http://blog.nationalarchives.gov.uk/blog/paddy-costello-soviet-spy-political-intellectual/

Surprisingly there is little or no mention of the fact that the man MI5 was so sure was a KGB agent, Desmond ‘Paddy’ Costello, would have been the sixth Cambridge spy they detected rather late in the day. ‘The Cambridge Five’, all bright young men from ‘good families’ studying at Trinity College or nearby Trinity Hall, were Kim Philby,Guy Burgess,Donald Maclean,Anthony Blunt and John Cairncross. Costello, a New Zealander, was doing a post -graduate degree at Trinity College in the 1930s when the Cambridge Communist cell was at its busiest. He knew Burgess and Philby who went on to become full-blooded spies and James Klugman who helped to recruit Cairncross as a spy. Klugman would later describe Costello as ‘one good comrade’.

Unlike Burgess,Philby and some other Cambridge Communists, Costello had a PF (Personal File) at MI5 while still a student. In October 1934 he donated £5 to the Communist Party newspaper the Daily Worker via a letter from a friend to CP headquarters in London. The letter only described him as ‘Comrade Costello who is at present in Germany’ but that was enough to get MI5 started on the trail. Using passport records they identified him as a student at Trinity  who in the words of MI5 chief Sir Vernon Kell ‘has come under Left intellectual influence during his time at college’. Kell consulted the police in New Zealand  who reported back that letters which Costello had sent from Berlin to his mother in Auckland showed ‘that her son is very much against the Nazi movement’.
After Cambridge Costello was appointed as a lecturer in classics at what was then known as The University College of the South West, later the University of Exeter. He and his wife, Bella or ‘Bi’, the daughter of Jewish immigrants from Russia, both joined the Exeter Communist Party. Costello took time off from lectures in 1937 to travel to Bombay carrying a gift of £500 from the British Communist Party to its Indian counterpart.
Costello’s academic career came to a sudden halt in 1940 when, as the files reveal, the Principal of the University College of the South West,Dr John Murray, wrote to the Chief Constable of Exeter to report that ‘I have today suspended Mr Costello from the service of the college’. MI5 were ‘quite clear from the Chief Constable’s file that this was on account of his Communist views’. Two days before his suspension an Exeter student who Costello knew well had been sentenced at the Old Bailey to six months in prison under the Official Secrets Act. The Council of the college later called upon Costello to resign and he did. Two other Exeter students were sent down for their Communist activities.
Now unemployed, Costello joined up and was promoted to a Captain in the New Zealand forces. In 1944 he was discharged in order to take up the post of Second Secretary at the New Zealand legation in Moscow. MI5 were told that ‘in spite of his left-wing tendencies he was selected for the post on account of his knowledge of Russian and his academic record’.

Roger Hollis of MI5 began an MI5 campaign to get Costello sacked. He contacted the Dominions Office in Downing Street which was the link with what later became the ‘White Commonwealth’ countries. By coincidence a former Cambridge left-winger of the same period, the splendidly titled Francis Edward Hovell-Thurlow-Cumming-Bruce, better known as Francis Cumming-Bruce, was working at the Dominions Office and vouched for Costello as a ‘decent, honest man, who like many undergraduates was seriously interested in Communism’. Coincidentally Cumming-Bruce went on to become the British High Commissioner in New Zealand, his own youthful interest in Communism having been forgiven or overlooked.

Hollis then got the Dominions Office to write to the New Zealand High Commission in London about the Exeter episode to say that Costello’s ‘close association with the man convicted necessarily raises a doubt whether he is a safe and suitable person to be employed by the New Zealand Government in his present capacity’. The High Commission wrote back to say that Costello had been ‘interviewed and as far as possible vetted by the Prime Minister’. He had an excellent war record that showed ‘he could be relied upon’. But they were not aware of Costello’s dismissal in Exeter and would raise it with the New Zealand Prime Minister. Later MI5 followed up by pointing out that Costello’s wife ‘still apparently a member of the Communist Party’ was on her way to Moscow to join her husband.
The New Zealanders did not take kindly to being reminded again about the Costello case. He was ‘one of the best people the New Zealand Department (of External Affairs) had’ and the advice from Wellington at the end of the war was that it would be ’wise not to pursue the question of Costello with the Department of External Affairs any further’.
Imagine Roger Hollis’s reaction at the Savoy Hotel in London four years later, in 1949, when a New Zealand diplomat told him that Costello was now being promoted to Charge d’Affaires in Moscow after the New Zealand Prime Minister decided Costello was ‘trustworthy’.

The following year Costello was promoted again, this time to a post in Paris, but on a trip back to New Zealand he went out drinking with old friends, was arrested for drunkenness and ‘spent the night in the cooler’.While there some remarks he made ‘caused the police sergeant to consider he possessed Communist views’,what Hollis called ‘in vino veritas’ evidence.

Eventually the New Zealand Government, constantly lobbied by the British and by now in the shadow of the defection of Burgess and Maclean in 1951, found it convenient to  force Costello out. He returned to academia but this time at the rather more exalted rank of a Professor, as Chair in Slavonic Studies at Manchester University.

MI5 now zeroed in on him and his wife. The files show the extraordinary lengths they went to in order to find evidence about ‘Desmond Patrick COSTELLO and Bella COSTELLO, who are known to have been Communists in the past, are suspected of working for the Russian Intelligence Service. It is desired to investigate their current activities and contacts.’ Among the documents is a very home-made ‘Map of Costello’s Home Area’ near Manchester and hour-by-hour reports from those MI5 and police men tasked with following the Costellos around the streets of Manchester and London .

At the end of it all MI5 had two things that convinced them the couple were spies but which would never have been enough for a court conviction. Mr Costello was seen having clandestine meetings with two Soviet officials believed to be intelligence officers and Mrs Costello’s handwriting was ‘written proof’ linking her to a document which could have been used to transfer the identities of long dead children to KGB spies.

Desmond ‘Paddy’ Costello died unexpectedly from coronary thrombosis in 1964 aged 52. MI5 closed their file without ever finding clear-cut evidence that they’d got their ‘sixth man’