The 36-year-old actor – who has played DS Phil Hunter for five years – has swapped one flirtatious character for another, landing the role of Max Branning’s (Jake Wood) brother and romeo ex-cop, Jack.
The move is the first time one soap has poached an actor from another and ITV bosses are said to be shocked by his "bombshell" decision to quit.
An ITV insider told The Sun: "He handed in his notice this week and broke the news to colleagues. Nobody had a clue before that.
"It’s come as a bombshell to the producers because they see Scott as a pivotal character. He’s been on the show for five years and is getting fed up with the direction of the show."
They added: "ITV has dictated changes, insisting on guests, basically trying to make it sexier. A lot of people are unhappy."
A spokesperson for The Bill told Digital Spy today: "We can confirm Scott Maslen is leaving The Bill at the end of his contract. Scott has been a fantastic part of The Bill team for the last five years, as the popular character DS Phil Hunter. We wish him all the greatest success for his next role."
And Scott told us: "I am very sad to be leaving The Bill, but after five years I wanted to explore new opportunities. The Bill has afforded me some fantastic storylines and I know they have some really great stories planned for the coming months.
"The show is enjoying fantastic ratings at the moment, so it's a good time to leave when things are on such a high."
BBC chiefs, meanwhile, are "overjoyed" and have "huge" plans for the new character.
A source told DS: "The women of Walford should watch out when Jack’s about. He just charms them into bed."
One told the newspaper: "Jack is used to getting his own way. He also tries it on with most of the women he comes across. The Mitchell sisters, Ronnie and Roxy, catch his eye from an early stage. It’s a great part for Scott to get his teeth into."
Speaking of his new role, Scott added: "I'm really looking forward to playing Jack Branning. He is an extremely competitive man who always likes to win in business and in pleasure."
Scott begins filming with the Walford soap next month and will first appear on screen in September.