Historical 'what-ifs' are always fascinating, and Maldon's Hythe was the scene of a plan that, had it gone ahead, would have changed the whole course of our history.

Henry VIII died in 1547, and was succeeded by the child king, Edward VI. Eagerly supported by his advisors, Edward took the country deeper into reform of the Church, imposing regulations that banned traditional Catholic practices and beliefs.

His half-sister, Princess Mary, adhered strictly to the Catholic faith of her beloved mother, Henry's first wife Catherine of Aragon. This was at first tolerated by Edward, and Mary was allowed to celebrate mass privately. But he grew increasingly frustrated, especially as she was a magnet for disaffected Catholics.

Mary had a powerful ally abroad in the form of Charles V, Holy Roman Emperor. The Holy Roman Empire at this time covered Austria, much of Germany, North Italy, Spain and the Netherlands (I can still hear my history teacher saying it was "neither holy, nor Roman, nor an empire.").

In April 1550, fearing for her liberty, Mary told the Imperial ambassador, Van der Delft, that she wished to flee to the Netherlands. She took up residence with the Fitzwalter family at Woodham Walter, an ideal location for spiriting her away via the Blackwater Estuary.

Van der Delft's secretary, Johan Dubois, was tasked with organising the escape. Three imperial warships arrived off the Essex coast on the evening of 30 June 1550. Dubois was rowed into Maldon from the ships, posing as a grain merchant. With tensions with the Continent increasing, the country was in a state of high alert, and Dubois' mission was perilous.

Mary, however, was getting cold feet. By leaving the country she would be abdicating all her rights as a true daughter of Henry VIII, and she speculated (with uncanny accuracy) that events in England might suddenly turn her way.

Mary's trusted officer Robert Rochester begged Dubois for more time. An increasingly frantic Dubois argued for immediate flight – the plot might already have been discovered, and time was running out.

With Mary still dithering, Dubois gave up and made his way back to the ships under cover of darkness. The plot was over, and Mary stayed.

Three years later, Edward VI was dead at the age of fifteen, probably of bronchial pneumonia. His planned successor was Lady Jane Grey, as fiercely Protestant as himself. But Jane Grey's support evaporated, and after nine days, Mary was swept in as Queen. Lady Jane was beheaded at the age of just sixteen, still proclaiming her faith.

Mary is remembered of course as the infamous "Bloody Mary" who oversaw the deaths at the stake of over three hundred religious dissenters. One of these was Stephen Knight who was burned in Maldon on 28 March 1555 at Fullbridge, and who is still commemorated by a small plaque on the Old Iron Works.

Had Mary fled that summer night, none of this would have happened. On Edward's death, she could only have returned at the head of an invading army, a very unwelcome proposition for a proudly independent English nation, however sympathetic many of them may have been to her religious views.

Lady Jane Grey would probably have been secure on the throne, and with her backers would have taken the country down an even more strongly Protestant path (such as that introduced by Oliver Cromwell a hundred years later).

With Princess Mary effectively disowned, it is likely that Princess Elizabeth, daughter of Anne Boleyn, would also have been sidelined, perhaps married off to a suitable candidate.