The Secrets of Station X (12 page)

W
hile the attacks on Army and air force Enigma had produced fairly rapid results once the fighting began, the German Navy Enigma was recognised as a far more difficult nut to crack. Frank Birch recalled being told by Denniston at the start of the war that ‘all German codes were unbreakable’. There was no point in ‘putting pundits onto them’ because nothing they could do would work, Denniston said. This was particularly true of Naval Enigma. According to Hugh Alexander, who was to become the head of the Naval Enigma section, ‘when the war started
probably
only two people thought that the Naval Enigma could be broken – Birch, the Head of German Naval Section, and Turing, one of the leading Cambridge mathematicians who joined GC&CS. Birch thought it could be broken because it had to be broken and Turing thought it could be broken because it would be so interesting to break it. Whether or not these reasons were logically satisfactory they imbued those who held them with a determination that the problem should be solved and it is to the pertinacity and force that, in utterly different ways, both of them showed that success was ultimately due.’

Turing himself admitted that his main reason for working on Naval Enigma rather than any other problem was because ‘no one else was doing anything about it and I could have it to myself’. He started where the Poles left off and for the first three months of the war concentrated on trying to work out the complex indicating system which was one of the factors that made Naval Enigma so much more difficult to break. He succeeded in December 1939 in solving the indicating system
using Polish decrypts for the first week of May 1937, but could not make any progress against wartime Naval Enigma without a ‘pinch’, the capture of original German cypher keys or settings.

Harry Hinsley had arrived at Bletchley in October 1939 aged just twenty, having been interviewed by Tiltman and Denniston in Charlesworth’s rooms at St John’s College, Cambridge, along with Bill Bonsall. ‘I was formally invited to join GC&CS about four days later,’ Hinsley recalled. ‘It was all done with minimum fuss and maximum dispatch.’ He was sent to Hut 4 and put in the care of Phoebe Senyard, who ensured he toured the Naval Section, learning what everyone was doing. Unlike many of the dons, Hinsley did not have a privileged background. He was a grammar school boy from Walsall, in the Black Country. His father was a wagoner who drove a horse and cart between the local ironworks and the railway station and Hinsley had won a scholarship to St John’s. A slight, bespectacled young man with wavy hair, he began working on traffic analysis of naval signals, putting together
intelligence
from the way in which the naval networks operated, where the individual stations or ships were located by direction-finding (DF), and the plain text messages that they passed. Following the original rehearsal, which the Naval Intelligence Division did not regard as having gone well, the Admiralty insisted that the GC&CS traffic analysts must work in the Operational Intelligence Centre (OIC) in London, which coordinated all naval intelligence. But the intelligence available from ‘log-reading’ or traffic analysis might be vital to finding cribs that would help Turing and Twinn, so Birch decided Hinsley must fill the gap together with a female intelligence analyst, 23-year-old Jocelyn Bostock, who was already working on the problem. The young and enthusiastic Hinsley was an immediate hit with Senyard.

‘I can remember quite well showing Harry some of the
sorting
and how delighted he seemed when he began to recognise the different types of signals,’ she said.

Relations between Hut 4 and the Admiralty were however far from cordial. While Hut 3 worked to the War Office and the Air Ministry via MI6, the Naval Section was officially NID12, part of the Naval Intelligence Division, and in direct contact with the OIC. But whenever any of the codebreakers attempted to talk to the intelligence officers in the Admiralty, their advice was virtually ignored.

‘Communication with the Admiralty was distinctly
primitive
,’ Hinsley recalled.

In the second half of May 1940, Hinsley began to report evidence that a number of German warships were about to break out of the Baltic. The OIC ignored his warnings.
This was to lead to one of the Royal Navy’s worst disasters of the Second World War, the sinking of the aircraft carrier HMS
Glorious
.

‘For about a fortnight beforehand, I pretty well rang the OIC once or twice a day and said: “Look you ought surely to pass a signal out on this. Can you possibly pass a signal out?”,’ Hinsley recalled. ‘They showed some interest. But were not sufficiently convinced to send a warning to the Home Fleet.’

On 7 June 1940, the
Glorious
and her two escort destroyers were spotted by a German flotilla which included the pocket battleships the
Gneisenau
and the
Scharnhorst
, Hinsley said.

The next day HMS
Glorious
and her two escort destroyers, HMS
Acasta
and HMS
Ardent
, were sunk with the loss of 1,500 men.

‘The
Glorious
was capable of making a limited torpedo strike and could have flown defensive patrols if she had received even a qualified warning,’ Hinsley said.

Bletchley Park’s warnings to the Admiralty were the subject of a sustained cover-up. Even today, and despite the fact that Hinsley
detailed the advice given to the Admiralty in the official history of British Intelligence in the Second World War, the Ministry of Defence still claims that ‘British intelligence sources failed to discover that the German force had sailed.’

After the sinking of the
Glorious
, the OIC began to take more interest in what Bletchley Park said, and the GC&CS traffic analysts who had been detached to the Admiralty were sent back to the Naval Section. ‘Steps were taken not only to improve the working relations between the operational and the intelligence staffs in the Admiralty, but also to bring the OIC and the Naval Section at GC&CS closer together,’ Hinsley said. ‘It was as a direct result of the loss of the
Glorious
that regular visits between the two groups were instituted and that the OIC recognised that it had to rely on Naval Section’s greater familiarity with the German naval wireless system and to co-operate with the Naval Section in relating this
knowledge
to other operational information. It did so with a will.’ Nevertheless, it was clear that some naval intelligence
officers
clearly resented its very existence. ‘There was more than a suspicion of professional jealousy,’ noted Charles Morgan, who served in Naval Intelligence. ‘It was almost a point of honour to find the answer from our own records, even if a trifle incomplete, rather than have recourse to a BP telephone extension.’

Reviewing what happened after the event, Birch had a more dispassionate view of the situation, identifying the problem as being more a case of the OIC not being persuaded of the reliability of the traffic analysis process. ‘Admiralty was by no means convinced of its reliability,’ Birch said,

In an apparent effort to heal the rift, Hinsley was called down to the Admiralty and even sent to visit the Home Fleet at Scapa Flow. This caused some minor problems since, like many of the civilians at Bletchley, Hinsley wore only casual clothes, corduroy trousers and jumpers, and had no presentable clothes. ‘Scrounger’ Green said he was called in by Birch and told ‘to produce a suit of clothes – a hat he would not wear – for a shining light who was summoned to the Admiralty and who had nothing else to wear but a pair of corduroys and a Fair Isle pullover’.

The new liaison had a limited effect, Hinsley recalled. ‘They began to realise that in spite of the fact that we were scruffy and young, and civilian, we had something to contribute. They took great pains thereafter always to be in close touch and always to argue and listen to us, taking the trouble to appoint a liaison officer to Bletchley to whom we could always show the facts.’ But despite the closer liaison, the difficulties continued. A few months later, Alec Dakin, an Egyptologist from Brasenose College who had been newly recruited into Hut 4, visited the Admiralty and was aghast to discover that the OIC appeared to be deliberately ‘obstructive and dismissive’ of Bletchley Park. Asked by Birch and Travis what was behind the problem, Hinsley blamed it on ‘a competitive spirit which instead of being of a healthy type is obviously personal. It couches itself in a show of independence and an air of obstruction. It appears to be based on personal opposition to Bletchley Park. I suspect that another reason for their inadequacy is incapacity pure and simple.’

Turing and Twinn were working on the German Navy’s ‘Home Waters’ cypher, which they dubbed
Dolphin
. ‘There were at the time only two (daily-changing) Naval Enigma keys – for home and foreign waters respectively,’ Birch said. ‘As the latter never carried enough traffic for cryptanalysts to work on, the Home Waters key was, in effect, the only objective.’

The Naval Enigma Section would eventually be housed in Hut 8 but at the beginning it was set up in a small corner
of Hut 4, the Naval Section’s base to the left of the mansion, Senyard said

The move to Hut 4 was followed by a key pinch. Two of the new wartime wheels for the Naval Enigma had been captured in February when the U33 was sunk while trying to lay mines in the Firth of Clyde, then on 26 April 1940, HMS
Griffin
captured a German Navy patrol boat, a converted trawler, off the Norwegian coast and towed her into the Orkneys. Unfortunately, after the German ship arrived at the naval base of Lyness, it was looted by British sailors looking for trophies. But some cypher tables and some sheets of signal pad on which encyphering had been carried out were recovered and these allowed Turing to confirm how the indicating system worked as well as providing him with letter for letter cribs for messages encyphered on the 25 and 26 April. The information on the relatively few pieces of paper that could be retrieved led to the breaking of six days’ worth of traffic, Birch said. ‘In fact, special intelligence from Naval Enigma might have been continuously forthcoming from then on – a whole year earlier than in the event – if the German trawler had not been looted before examination.’ Even with the captured material, the keys for 26 April were difficult to get out. Since the
first Bombe, nicknamed
Victory
, had been introduced in March 1940, it was used to find the solution. It was a measure of the difficulties involved both in breaking Naval Enigma and with the first Bombe that it took a fortnight before it finally came up with the answer, scarcely a practical solution to solving Naval Enigma. Welchman’s clever modification to the Bombe, known as the diagonal board, would make it much more efficient, but the Bombes fitted with the diagonal board would not be
introduced
until August.

The frustration felt by Hut 8 and in the Naval Section was exacerbated by the fact that the entire second half of 1940 ‘produced depressingly few results’, while the German
submarines
, the U-Boats, began to cut into the vital Atlantic convoys bringing food, machinery and oil to the UK. The Fall of France had given the U-Boats new bases on the French Atlantic coast that allowed them much easier access to the Allied convoys in what was effectively the beginning of the Battle of the Atlantic. The U-Boats used the
Rudeltaktik
, or ‘wolf pack’ tactic, devised by their commander Admiral Karl Dönitz while he was a
prisoner
of the British during the First World War. The German Navy had broken the British Merchant Navy Code and was reading many Royal Navy operational messages so the wolf packs knew the routes to be taken by the convoys and could lie in wait.