Are the curtains tightly drawn? Is the door locked and bolted? Have you electronically swept the room for listening devices to ensure that you are not bugged?

Great Yarmouth Mercury: BARRACKS BIRTHPLACE: The cannons-flanked entrance (right) to the Yare-side armoury on Southtown Road in 1885, opposite the Gordon Road and Albany Road stretch, where Vernon Kell was born, 12 years before this wintry north-facing picture was taken. Picture: COLIN TOOKE COLLECTIONBARRACKS BIRTHPLACE: The cannons-flanked entrance (right) to the Yare-side armoury on Southtown Road in 1885, opposite the Gordon Road and Albany Road stretch, where Vernon Kell was born, 12 years before this wintry north-facing picture was taken. Picture: COLIN TOOKE COLLECTION (Image: Archant)

Then OK, it is safe for you to begin reading today’s column...without the danger of your Mercury self-destructing within five seconds, as did top secret “for your eyes only” messages in the Mission Impossible television series back in the Nineties.

Or, in ‘Allo! ‘Allo! comedy mode, I will say this only once...

The information I am about to disclose is not widely known to the general public. It came to light only because one of the readers who sometimes provide me with topics for this column had second thoughts, and double-checked. He might have made a good spy, or at least an analyst of highly classified information.

Let me put it in the words of that regular contributor, Trevor Nicholls, the long retired former Great Yarmouth registrar: “I was mooching around the public library when a bulky volume caught my eye – The Authorised History of MI5. I took it off the shelf, put it back, changed my mind again, took it off the shelf once more and sat down to browse.

Great Yarmouth Mercury: HARD WORK! A cannon barrel is dug up at the armoury site in 1982 by members of Great Yarmouth and District Archaeological Society: (l-r) Colin Tooke, Ted Goate and Jim Holmes.Picture: COLIN TOOKE COLLECTIONHARD WORK! A cannon barrel is dug up at the armoury site in 1982 by members of Great Yarmouth and District Archaeological Society: (l-r) Colin Tooke, Ted Goate and Jim Holmes.Picture: COLIN TOOKE COLLECTION (Image: Archant)

“I was equally astonished and amused to learn that Britain’s spymaster-in-chief had been born in Great Yarmouth!”

Did a chill run down Trevor’s spine? Was his forehead bathed in a sudden cold sweat? Was a hidden surveillance camera recording his every move? Would a shadowy figure emerge from behind the bookshelves to utter the dreaded words: “Now I shall have to kill you, Mr Nicholls. You know too much.”

None of the above, apparently, although perhaps a camera was ensuring that library users were not misbehaving or ill-treating books.

Sadly, Yarmouth cannot take more than a modicum of credit for being the birthplace of a man destined to attain status and immense power in the defence of the realm. He was not a member of any long-established Yarmouth family – and even today, there is nobody of his surname in the Norwich and North Norfolk telephone directory.

Vernon George Waldegrave Kell just happened to be born hereabouts. But, as befits a man privy to the nation’s secrets in his professional career, even his birth here in November 1873 has a figurative small question mark after it.

Drawing on information in The National Biography, The Authorised History of MI5, the on-line encyclopaedia Wikipedia, associated websites and the 1911 Census of Population, Trevor tells me that Vernon Kell was born at the military arsenal, armoury and barracks in Southtown, then officially part of the Mutford registration district in Suffolk, as was all of Gorleston until the 1891 creation of the county borough of Great Yarmouth.

His father was Major Waldegrave Charles Vernon Kell, of the 38th Foot, with distinguished service in the Zulu Wars and other out-posts of empire. His mother, Georgiana Augusta Konarska, later divorced, was the daughter of a Polish count with a string of exiled relatives across Europe.

But one tome claims that Vernon Kell was born while his mother was enjoying a seaside holiday here, although my correspondent points out: “That might well have been so, but his father could have been stationed at Yarmouth at the time, and Mrs Kell came down to visit. Troops were forever passing through the town at that time. Vernon Kell liked to say, in family circles, that he was a Yarmouth Bloater.”

Trevor Nicholls points out that during his registrarship here, it was not uncommon for a baby to be born prematurely while its parents were visiting the town on holiday.

He continues: “Kell had a private education and cosmopolitan upbringing, and travelled widely on the Continent to visit friends and relatives. Described as the most accomplished linguist ever to head a British intelligence agency, his widow said he had five languages as the result of his travels.”

After military college at Sandhurst, Kell joined his father’s regiment as an officer interpreting French and German, then visiting Moscow in 1898 to add Russian to his linguistic skills. Two years later, newly married to Constance, he headed for Shanghai to learn Chinese, witnessing the Boxer Rebellion.

Back in London, he was German intelligence analyst at the War Office, then assistant secretary to the Committee for Imperial Defence.

Trevor Nicholls found that in 1909, when Kell was 36, he joined with a naval officer, Mansfield Cumming, to head a new secret intelligence service. “Kell would later be credited with destroying the German spy network in Great Britain,” according to Trevor’s researches.

In 1910 the home and overseas secret services were separated, Kell heading MI5 as its first director and Cumming the SIS that later became the shadowy MI6. Kell and his successors were all known by his initial, K (not M, as in the James Bond novels), and he was to become the longest serving head of any British Government department or agency in the 20th century.

In 1911 Kell, his wife, their three children, his sister-in-law and four servants were living in a house in Surrey, according to that year’s census. Trevor notes: “The servants included a German governess, Anna Seiz, aged 35, from Silesia.

“Kell, who thought the country was being flooded with German spies and was taken to be a Germanophobe, nevertheless employed a German to teach his children, a fact noted by the authorised history of MI5.”

However, by 1940 MI5’s central registry was in such a mess that Prime Minister Winston Churchill called for Kell’s resignation. During his brief retirement Kell became a special constable.

The life of Britain’s senior spy-master, which had begun 68 years earlier at a military establishment built between Southtown Road and the River Yare, concluded with a funeral which was almost a semi-state occasion, continues Trevor.

“Those gathered in the church in Buckinghamshire knew his name, they might have thought that they knew him, but it is reasonable to suppose that very few indeed were aware of his true background, and none (his most senior colleagues apart) the secrets to which he had been privy for over 40 years.”

Apology: The caption to the 1979 photograph of the late Paul Daniels illustrating last week’s column wrongly identified his Britannia Pier co-star, Karen Kaye, as his future wife, Debbie McGee.