William Francis Forbes-Sempill, 19th Lord Sempill, , (24 September 1893 – 30 December 1965) was a Scottish peer and record-breaking air pioneer, who was later shown to have passed secret information to the Imperial Japanese military before the Second World War. Educated at Eton, he began his career as a pilot in the Royal Flying Corps, and then served in the Royal Naval Air Service and Royal Air Force during the First World War. In 1921, Sempill led an official military mission to Japan that showcased the latest British aircraft. In subsequent years, he continued to aid the Imperial Japanese Navy in developing its Navy Air Service.
In the 1920s, Sempill began giving military secrets to the Japanese. Although his activities were uncovered by British intelligence, Sempill was not prosecuted for spying and was allowed to continue in public life. He was eventually forced to retire from the Royal Navy in 1941, after being discovered passing on secret material to Tokyo shortly before Japan attacked Pearl Harbor and declared war on the United States and the British Empire.
Sempill was known as "Master of Sempill" before succeeding his father to the titles of Lord Sempill and Baronet of Craigevar in 1934.
Early life Born at the family seat of Craigievar Castle in Aberdeenshire, Sempill was educated at Eton, although in November 1907, having studied there for a year, he ran away, eventually making it to Craigievar before being discovered. Following this incident, he was privately tutored. In 1910, Sempill was apprenticed to Rolls-Royce.
In November 1913, Sempill offered his services to the Stackhouse Antarctic expedition, planned for the following year. He was supposed to serve as chief of the meteorological department, but with the outbreak of the First World War, the expedition was cancelled.
Military and civil aviation At the outbreak of war, Sempill joined Royal Flying Corps, being granted a probationary commission as a second lieutenant on 15 August 1914, which was confirmed less than four months later. In the meantime Sempill was appointed to flying duties. The following year, in February, Sempill took up a position as an "experimental officer" at the Central Flying School, and he received a promotion to lieutenant in April. Less than four months later he was appointed a flight commander with the temporary rank of captain. In August 1915, he was appointed to instructional duties. Sempill's time at the Central Flying School was not to last, as he relinquished his Army commission at the end of the year on being accepted for temporary service in the Royal Naval Air Service. Sempill's rapid rise through the ranks continued in the Navy, and at the close of 1916 he was promoted to squadron commander. On 1 April 1918, with the amalgamation of both flying services into the Royal Air Force, Sempill was transferred, and was appointed one of several deputy directors in the RAF's personnel department with the temporary rank of colonel. He was awarded the Air Force Cross in the 1918 Birthday Honours. Sempill stayed at the Air Ministry until 8 October 1918, when he was seconded to the Ministry of Munitions. On the cessation of hostilities, he became a test pilot,Peter C Smith, Fist from the Sky and he retired from military service in 1919.
On 4 September 1930, he set a new record by flying a de Havilland DH.80 Puss Moth seaplane (G-AAVB) 1,040 miles non-stop from Brent Reservoir in London to Stockholm, Sweden, in 12 hours.Lewis (1970), p. 214 On 26 March 1936, he made a record-breaking flight in a BAC Drone ultra-light aircraft (G-ADPJ) 570 miles from Croydon Airport direct to Berlin Tempelhof Airport in 11 hours. He flew back a day or so later in 9 hours though he interrupted the flight with a stop at Canterbury, Kent.
In early 1931, Sempill was appointed chairman of National Flying Services, the government-subsidised owner and operator of London Air Park, Hanworth. On 22 March 1931, he hosted a visit by members of the Japanese Royal Family and the Japanese Ambassador to Britain. He arranged and hosted a widely publicised visit of the German airship LZ 127 Graf Zeppelin to Hanworth on 18 August 1931. On 2 July 1932, the airship returned as part of a round-Britain tour.
Japanese spy Beginnings In 1920, he led a civilian British deputation of former naval airmen to Japan – the Air Ministry and the Foreign Office saw the prospect for lucrative arms contracts with Japan – to help develop aircraft carriers, and to assist the Japanese navy in setting up its new air base,Cheesman, Frank Prelude to Pearl Harbour article in Aircraft Annual 1964 UK Ian Allan 1963 pp24-29 after the Japanese had bought three Supermarine Channel flying boats. Sempill was well respected within Japanese circles, and received a personal letter from Prime Minister Tomosaburo Kato (1922–1923), thanking him for his work with the Imperial Japanese Navy, which he described as "almost epoch-making."
With the termination of the Anglo-Japanese Alliance in 1921, Sempill should have ended close military contact and discussions regarding naval aviation technology and tactics. However, on his return to the United Kingdom in 1923, Sempill kept in contact with the Japanese Foreign Ministry through the Japanese Embassy in London.
Suspicion and questioning
In 1925, Sempill accompanied a mission of foreign air officials to the Blackburn Aircraft factory at Brough, East Yorkshire. The Japanese had previously asked questions about aircraft being developed. Sempill later asked the same questions, in his official capacity, about the then-secret Blackburn Iris.
The Directorate of Military Intelligence had kept Sempill's communications with the Japanese intelligence officer/Naval attaché in London, Captain Teijirō Toyoda, under surveillance from 1922. This led to the knowledge that Sempill was passing classified information to the Japanese that Toyoda's communications indicated had been paid for. MI5 tapped Sempill's phone, and observed that his servant was a Japanese naval rating.
In March 1926, Sempill was proposed by the Aviation Ministry for an appointment as Greece's aeronautical adviser. At this point, the Directorate of Military Intelligence advised the Foreign Office and the British Embassy in Athens that Britain could not be seen to endorse Sempill's appointment because of his past activities.
Sempill was called into the Foreign Office for questioning. The questions directed to him were intended to assess his loyalty to the British Government, his attachments to the Japanese, and the amount of information that he had passed to the Japanese. During the interrogation, the MI5 investigating officer could not reveal that the British had broken Japanese codes, and were monitoring the Japanese communications systems.
On a trip to Brough, Sempill had openly talked about the Iris flying boat with the foreign air officials on the train trip from London. This was witnessed by a British Air Ministry civil servant, who reported the incident. Upon being confronted with this information, Sempill admitted to the investigation officer that he had broken the Official Secrets Act.
A subsequent meeting, chaired by the Secretary of State for Foreign Affairs Austen Chamberlain, decided it was not in the interests of the British government to prosecute Sempill for violating the Official Secrets Act. Firstly, Sempill's father was then aide-de-camp to King George V; any public trial would be a grave embarrassment to both the Crown and the British establishment. Secondly, a prosecution would have revealed to the Japanese that British Intelligence had cracked the cypher codes of its diplomatic service.
Reprieve and inter-war activities Six years after admitting he had breached the UK's Official Secrets Act, Sempill became a technical and business consultant to Mitsubishi Heavy Industries; from 1932 to 1936, he represented the Japanese company in Europe. He also became chairman and then president of the Royal Aeronautical Society. In this capacity, he advised overseas governments, such as Australia, on the creation of their naval air services.
In October 1933, Sempill was seriously injured in an accident while riding as a passenger in a prototype Dymaxion three-wheel car in the United States. Sempill had been invited, in his capacity as an aviation expert, to review the aerodynamic experimental vehicle at the Chicago World's Fair. As he was being rushed to an airport to catch a plane to Akron, Ohio, to meet the Graf Zeppelin for its return trip from New York to Europe, the Dymaxion was struck by another vehicle, and overturned, killing the driver and injuring Sempill.
On 28 February 1934, he succeeded his father, John Forbes-Sempill, 18th Lord Sempill, as Lord Sempill and Baronet of Craigevar. His wife Eileen, who had accompanied him on many of his air tours, died in July 1935.
Sempill had "an affinity with militarist right-wing regimes". During the 1930s, he developed extreme right-wing political opinions, and was active in several antisemitic organizations such as the Anglo-German Fellowship, the pro-Nazi Link organisation, and The Right Club led by Archibald Ramsay.
Espionage 1939–1941 On the outbreak of war in 1939, Sempill was given a position in the Department of Air Materiel at the Admiralty. This gave him access to both sensitive and secret information about the latest British aircraft.
By June 1941, MI5 had intercepted messages between London and Mitsubishi and Marshal Yamagata's Tokyo headquarters indicating payments were being made to Sempill: "In light of the use made of Lord Sempill by our military and naval attaches in London, these payments should continue". On further investigation, MI5 suspected that Sempill was passing on top secret information about Fleet Air Arm aircraft. The matter was passed to the Attorney General and Director of Public Prosecutions. Once more, the Attorney General advised against prosecution. On 5 September 1941, Sempill attended a meeting with the Fifth Sea Lord, and was given "a strict private warning".
On Friday 2 August 1940, Special Branch arrested Japanese businessman Makihara Satoru, head of Mitsubishi Shoji Company's London office, and several others on suspicion of espionage, and took them to Brixton prison. On discovering that Makihara was in custody, Sempill telephoned and then called at Paddington police station to assure the police of Makihara's innocence and character. He was released a few days later, on Monday 5 August, due to "insufficient evidence".
Sempill was also probably passing on detailed information about the British government. In August 1941, Winston Churchill and President Franklin D. Roosevelt held a meeting in Newfoundland aboard HMS Prince of Wales to discuss the military threat posed by the Japanese. Soon after, communications between the Japanese embassy in London and Tokyo were deciphered by the Bletchley Park code breakers. The decrypted messages were transcripts of the conference notes. When passed to an alarmed Churchill, he called them "pretty accurate stuff". Three months later, more notes from Churchill's personal agenda and inner circle were intercepted as they were being sent by the Japanese Embassy in London to the Foreign Ministry in Tokyo. Privately, Churchill concluded with Anthony Eden that only two men could be the source of such leaks: Commander McGrath or Lord Sempill.
On 9 October 1941, a signed note from Churchill read: "Clear him out while time remains." The following week the Admiralty told Sempill he must either resign or be sacked.