Back in 2018, Gary Oldman won the Best Actor Oscar for his portrayal of Winston Churchill in Darkest Hour.

The World War II film depicted his rise to become Prime Minister as Allied troops evacuated France and Hitler considered invading the British Isles.

However, a historian claims that although this 1940-1 period was Britain’s Darkest Hour, it certainly wasn’t Churchill’s.

Philip Kay-Bujak exclusively tells Express.co.uk that another incident over 20 years prior “has all been very cleverly airbrushed by the establishment around the Churchill myth” and that “I certainly do not rate Churchill as the greatest man in British history – far from it.”

For this historian, the World War II PM’s real Darkest Hour came about thanks to Lt Col John Sherwood Kelly, a courageous rebel and the subject of his book The Bravest Man in the British Army.

The historian shared: “Churchill’s Darkest Hour was in 1919 when Lt Col John Sherwood Kelly decided to try to bring Churchill down and destroy his political career by exposing his secret plan to kill off the Bolshevik Revolution. Prime Minister David Lloyd George had ordered Secretary of State for War Churchill not to get involved and not to try to save the Russian Royal family. But Churchill, in his typical way, ignored his instructions and put together a 'volunteer' force of officers and 5000 men to travel in secret to Archangel, Russia in May 1919. This was ostensibly to rescue British soldiers and munitions from Lenin and the Bolsheviks but actually was to get to Moscow and help destroy the revolution. The men were ordered to go while six Victoria Cross winners volunteered for the operation. When Kelly realised, they were being used, he complained and when he was relieved of his command for 'losing his head' he wrote to the British Press - specifically the Daily Express!”

On September 6, 1919, this very newspaper published Kelly’s leak of the scandal that almost brought down Churchill’s political career under the assertion that “the British public have been humbugged.”

Kelly’s letter read: “To the Editor of the Daily Express: Sir – I have just returned from North Russia under circumstances which compel me to seek the earliest possible opportunity of making known in England certain facts in connect with North Russia which otherwise might never come to light.”

He shared how he volunteered for service with the North Russian Relief Force in the sincere belief that relief was needed to withdraw exhausted troops, ahead of affairs in North Russia being “would up in an efficient and decisive manner,”

Kelly had been placed in command of the 2nd Battalion, the Hampshire Regiment but soon discovered upon arrival in Archangel that the defensive forces were being used on the offensive.

He summed up, “I saw British money fired out like water and invaluable British lives sacrificed” and said how he saw it as his duty to share the news back in England despite what the consequences might be for him.

Bujak added that, as result, “questions were asked of Churchill in the House of Commons, there was outrage from the Trades Union Congress at Britain helping to crush fellow socialist workers in a foreign country and Lloyd George had a fit.

“Kelly had support in the shadows both financially from South African millionaires and also within the British establishment who wanted to see the back of Churchill. However, Kelly lost his courts martial and his career while Churchill only just survived what I would claim was Churchill's personal 'Darkest Hour’.”