James stars in new BBC series King & Conqueror(Image: BBC)

A highly-anticipated historical drama made its debut on BBC One on Sunday evening.

But within moments of the opening, viewers all voiced the same gripe as they highlighted several major flaws with the new show.

Featuring James Norton and Nikolaj Coster-Waldau as feuding monarchs Harold Godwinson and William of Normandy, King & Conqueror chronicles the events leading up to the Battle of Hastings.

The eight-part series follows the two nobles as they first encounter each other at King Edward’s coronation in England, where Harold’s cautions about betrayal fall on deaf ears. The inaugural 50-minute instalment witnessed William’s arrival in England for a crucial Royal wedding, planting the foundations of an epic feud through some brutal sequences.

Yet within minutes of the programme beginning, disappointed fans took to social media to express their frustration.

King & Conqueror landed on BBC Ones(Image: BBC / CBS Studios)

James reveals that while Nikolaj is “a brilliant actor and a wonderful man”, life began to imitate art as he felt the need to challenge his on-screen enemy when the cameras stopped rolling.

“We had Team Harold and Team William – we would jokingly spar about which storyline was more interesting,” says James, 40. “We leant into the head-butting that Harold and William do in the script, and as a result, there was a gentle, boyish competitiveness between the two of us. We hung out a lot and went jet skiing – I remember racing him across the water and thinking ‘this is very Harold of me’!”

While British schoolchildren have always been taught that Harold was the hero and William the villain of the Battle of Hastings, both James, who is an executive producer on the series, and Nikolaj were keen to tell both sides of the story that leads up to their meeting on the battlefield.

“I met President Emmanuel Macron at the British Museum, where the Bayeux Tapestry is moving to, and I was very quick to reassure him that we had told the French story, the Norman story, with as little bias as possible,” says James. “There are a lot of stories about William post Battle of Hastings, and how he acted pretty monstrously, but he also had his own domestic space, his relationship with his wife Matilda [Harry Potter actress Clémence Poésy] and his son.”

“Nikolaj brought so much complexity to that role and, as a result, I think the show feels balanced. We didn’t want one hero or one villain, we wanted the audience to be split and we wanted people to sit on the sofa and have someone on Team Harold and someone on Team William.

“I said to Macron, ‘I promise you that we have been fair in depicting both sides of the story,’ and a lot of that was to do with Nikolaj’s brilliant, sensitive performance.”