A short history of Bletchley Park

Early History

Fifty miles (80km) north-west of London lies Bletchley Park. In 1883, it became home to the Leon family, whose patriach was a wealthy City of London financier. Herbert Samuel Leon bought over 300 acres of land beside the London and North-Western Railway line that passed through Bletchley, Buckinghamshire, developing sixty of those acres into his country estate. At the heart of the estate, he built a mansion in a curious mixture of architectural styles. One of Bletchley’s greatest benefactors, he was much loved by the local people. He was awarded a baronetcy in 1911.

Following the deaths of Sir Herbert and Lady Fanny Leon, the Park fell into the hands of property developer Captain Hubert Faulkner, who intended to demolish the buildings and sell the land as a housing site.

But the Government was about to intervene. It was 1938 and the threat of war loomed as Hitler invaded first Austria and then Czechoslovakia. The Government Code and Cypher School, then based in London, needed a safer home where its intelligence work could carry on unhindered by enemy air attacks. At a junction of major road, rail and teleprinter connections to all parts of the country, Bletchley Park was eminently suitable.

Commanded by Alastair Denniston, the Park was given the cover name Station X, being the tenth of a large number of sites acquired by MI6 for its wartime operations.

After meticulous preparation and a series of trial runs, the codebreakers arrived in earnest in August 1939. They masqueraded as ‘Captain Ridley’s Shooting Party’ to disguise their true identity. It was to be the first instalment in one of the most remarkable stories of the Second World War.

Bletchley Park in WWII

The Enigma cypher was the backbone of German military and intelligence communications. Invented in 1918, it was initially designed to secure banking communications, but achieved little success in that sphere. The German military, however, were quick to see its potential.

They thought it to be unbreakable, and not without good reason. Enigma’s complexity was bewildering. The odds against anyone who did not know the settings being able to break Enigma were a staggering 150 million million million to one.

The Poles had broken Enigma in 1932, when the encoding machine was undergoing trials with the German Army. They even managing to reconstruct a machine. At that time, the cypher altered only once every few months. With the advent of war, it changed at least once a day, effectively locking the Poles out. But in July 1939, they had passed on their knowledge to the British and the French. This enabled the codebreakers to make critical progress in working out the order in which the keys were attached to the electrical circuits, a task that had been impossible without an Enigma machine in front of them.

Armed with this knowledge, the codebreakers were then able to exploit a chink in Enigma’s armour. A fundamental design flaw meant that no letter could ever be encrypted as itself; an A in the original message, for example, could never appear as an A in the code. This gave the codebreakers a toehold. Errors in messages sent by tired, stressed or lazy German operators also gave clues. In January 1940 came the first break into Enigma.

It was in Huts 3,6,4 and 8 that the highly effective Enigma decrypt teams worked. The huts operated in pairs and, for security reasons, were known only by their numbers. The codebreakers concentrating on the Army and Air Force cyphers were based in Hut 6, supported by a team in the neighbouring Hut 3 who turned the decyphered messages into intelligence reports. Hut 8 decoded messages from the German Navy, with Hut 4 the associated naval intelligence hut. Their raw material came from the ‘Y’ Stations: a web of wireless intercept stations dotted around Britain and in a number of countries overseas. These stations listened in to the enemy’s radio messages and sent them to Bletchley Park to be decoded and analysed.

To speed up the codebreaking process, the brilliant mathematician Alan Turing developed an idea originally proposed by Polish cryptanalysts. The result was the Bombe: an electro-mechanical machine that greatly reduced the odds, and thereby the time required, to break the daily-changing Enigma keys.

Recent History

With the declaration of peace, the frenzy of codebreaking activity ceased.

On Churchill’s orders, every scrap of ‘incriminating’ evidence was destroyed. As the Second World War gave way to the Cold War, it was vital that Britain’s former ally, the USSR, should learn nothing of Bletchley Park’s wartime achievements.

The thousands who had worked there departed. Some continued to use their remarkable expertise to break other countries’ cyphers, working under a new name: the Government Communications Headquarters (GCHQ).

The site became home to a variety of training schools: for teachers, Post Office workers, air traffic control system engineers, and members of GCHQ. In 1987, after a fifty-year association with British Intelligence, Bletchley Park was finally decommissioned.

For decades, the codebreakers would remain silent about their achievements. It was not until the wartime information was declassified in the mid-1970s that the truth would begin to emerge. And the impact of those achievements on the outcome of the war and subsequent developments in communications still has not been recognised fully.

The Bletchley Park Trust

The Struggle to Save Bletchley Park for the Nation
Post-war Bletchley Park became home to a variety of organizations including the General Post Office (GPO), the Civil Aviation Authority and a Teacher Training College whose numerous collective employees knew nothing about the enormity of the wartime work that had gone on in the buildings they inhabited.

In 1974 FW Winterbotham, who had worked on Ultra at wartime Bletchley Park, published a book called ‘The Ultra Secret’; an extensive, although at times inaccurate, account of the work and accomplishments of the codebreaking hub. So the secret was out and the ban on talking about it was lifted although detail about ‘Britain’s Best Kept Secret’ emerged only gradually and sporadically over the years that followed.

In 1991, many of the organizations who had occupied post-war Bletchley Park had moved out and there were moves to demolish the whole site in favour of housing development and a supermarket.  In May of that year Bletchley Archaeological and Historical Society formed a small committee with the aim of tracing as many Bletchley Park Veterans as they could to invite them to a Farewell Party to mark the demise of the Bletchley Park site where they had helped shorten WW2 by two years.  On 21 October the Farewell Party was attended by over 400 veterans and the small committee of local enthusiasts was astonished and enchanted by the powerful stories these incredible people had to tell about their wartime codebeaking experiences.  At the end of the event the committee was unanimous in its conviction that this must not be a farewell.  That Bletchley Park must be saved in tribute to the work of these amazing people and as the place where their collective intellects changed the course of WW2 and the twentieth century; that the story must be kept alive for the education and enjoyment of future generations.  So the enormous battle that was to ensue for many years, to save Bletchley Park from demolition, was embarked upon.

On 10 February 1992, a young Milton Keynes Councillor, Sam Crooks had persuaded Milton Keynes Council to declare most of the remainder of the Park a conservation area by ensuring Tree Preservation Orders had been secured on the Park’s trees.  Three days later the Bletchley Park Trust was formed and embarked on complex and lengthy negotiations with the landowners PACE (Property Advisors to the Civil Estate), the government’s land agency, and British Telecom.

The small committee of local enthusiasts grew and recruited many more passionate supporters and volunteers until in 1994 the Bletchley Park Trust and its Chief Patron, HRH The Duke of Kent, opened the site to the public as a museum every other weekend.  Although the landowners had withdrawn all planning applications there was no protection from the hostile bids of property developers.  The future of the Park remained hanging in the balance for five years until 10 June 1999 when the Bletchley Park Trust, secured a pioneering deal with the landowners.  The Trust was awarded a 250 year leasehold of the core historic areas of the Park with an option to purchase it for a nominal sum 25 years later.  The battle was not over but this was a hugely significant step towards saving Bletchley Park for the nation.

By 2004, the Trust was opening the Park to the public every day as a museum.  In April 2006 Simon Greenish was appointed the new Director of the Bletchley Park Trust.  Against all odds through the sheer determination, passion and hard work of the Trust’s army of volunteers and supporters and its tiny team of staff, the Trust was surviving.  But only just.  In spite of all of its successes, Bletchley Park had reached a critical point.  Minimal maintenance had been undertaken on the site since the war and its buildings were in a desperate state of disrepair; with the codebreaking huts rotting and with the iconic mansion suffering major roof leaks endangering the very fabric of the building.

In the nick of time, in November 2008, English Heritage stepped in with investment of £330,000 to repair the mansion roof at the same time offering a further £100,000 per year for the following three years, subject to another body offering match funding, to deal with the huge backlog of maintenance and repairs.  Early in 2009, Milton Keynes Council went to the public vote as to whether they should provide this funding and responding residents voted overwhelmingly in favour.  A further landmark was reached in October 2009 when the Heritage Lottery Fund announced a first round pass for the Bletchley Park Trust application for museum development funding and awarded £460,000 to work up detailed plans.  These will be submitted early to mid 2011 in a bid to secure the £4.1 million needed to realize the plans and subject to the Trust raising the £1 million needed for match-funding the bid.  The Trust will then work on raising a further £4 million to complete the development.

Today the Trust has come a very long way from the early days of small committee meetings in the homes of the founding members.  Over the years, and against all odds, it has passionately fought and overcome the numerous and perilous threats to the very existence of Bletchley Park.  For the first time it can now balance its budgets but its finances still quiver on a knife-edge.  In addition to raising the £1 million needed to support its HLF bid it also needs short-term assistance of in the region of £250,000 per year to support its operational costs. The objective of the Trust now is to transform Bletchley Park into the world-class heritage and education centre it deserves to be, reflecting the profound significance of its impact on us all.  Its business plan shows that once the museum development has been completed, in the next three to five years, the Bletchley Park Trust will be self-supporting.

The journey of the Bletchley Park Trust continues.

The history of Bletchley Park is, to an extent, still shrouded in mystery. Whilst every effort has been made to ensure the accuracy of this information, Bletchley Park Trust is unable to accept liability for information contained on this site, or in any other publication. If you should uncover an error, please let us know so that we may set the record straight. Please see the Contact Us section of this site for details.