Royal outrage: Viewers raged Edward VIII's 'treachery' meant he should have been 'EXECUTED

Edward VIII famously gave up the throne to marry divorced American socialite Wallis Simpson in 1936. However, the Duke of Windsor's abdication - just 326 days after he took to the throne - is far from the only stain on his royal record. Britain's former monarch shockingly harboured sympathies for Adolf Hitler and even encouraged the Nazis to bomb Britain into submission during World War 2.

The astonishing details about the disgraced King's life are explored in 'Edward VIII: Britain's Traitor King'.

The new Channel 4 documentary, which aired on Sunday, is based on royal historian Andrew Lownie's book 'Traitor King', an updated version of which will be published in May.

After years of painstaking research and archive work, the expert has built up a stark profile of Edward, including his moves against Britain and his younger brother, King George VI during World War 2.

Viewers of the new documentary were left astounded by the former monarch's "treachery" and said that he should have been "executed" for his actions.

Twitter user hutch__man said: "Watching Edward VIII: Britain's Traitor King.

GETTY Royal outrage: Viewers raged Edward VIII's 'treachery' meant he should have been 'EXECUTED'

GETTY Edward VIII: With wife Wallis Simpson

"Mind boggling the treachery and vanity of the man."

Another commenter, Simon Hudson said: "Why wasn't Edward VIII executed for treason? He was a traitor.

"Chamberlin's and Churchill's governments, the BBC and others of the establishment were all party to a cover up.

"One rule for them and another for us has been going on for centuries and still goes on today."

He added: "He encouraged the Nazis to bomb England. My family in London suffered the agony and devastation of that and many people were killed.

GETTY Hitler: With Edward and Wallis during German tour

"If I were around in 1940 and had known about it I would've called for his prosecution and death as I'm sure so many others would have. Sickening."

Edward's treachery is laid bare in an archived diplomatic cable from the German ambassador to the Portuguese authorities during World War 2,

He is said to have claimed to officials in Spain, which was ruled by Fascist dictator General Franco at the time, that "continued severe bombing would make England ready for peace".

Appearing in the documentary, Mr Lownie said: "Edward wanted to come back as a pro-Nazi leader.

"He characterises himself as a firm supporter of a peaceful arrangement with Germany.

GETTY Hitler: With Edward and Wallis during German tour

"He was so disloyal to his brother, he was calling for the bombing of Britain as a way of subjugating them.

"The Duke encouraged the Germans to bomb London and indeed, that's what they do."

On September 13, 1940, the Nazis bombed London, including Buckingham Palace, where Edward's brother King George VI and his wife Queen Elizabeth, the Queen Mother narrowly escaped with their lives.

Mr Lownie said: "The Duke definitely believes the continued severe bombing would make England ready for peace.

 GETTY Bombed: George VI and Queen Mother at Palace

"It is extraordinary - here is the former king of Britain saying if you bomb his family and country, it's the best way to bring the pursuit of peace.

"He's prepared to go to those lengths to achieve those aims. It's chilling and sinister and very shocking."

'Edward VIII: Britain's Traitor King' is available to stream on All 4.