Analysts predict a bid war, with UBS saying the bid could go to 1500p.
Some City sources think Sky’s highly rated management – including chief executive Jeremy Darroch, might be keen to move on whoever owns the company in the future.
Roberts said he was optimistic they would stay. “We’ve had several contacts. We have expressed to the board that we feel the management team is outstanding.”
“We see a good fit,” he added.
Comcast said its promises to protect Sky News match or exceed those from Fox. Its budget would be no lower than it was last year for the ten year period, it pledged.
Fox has called on regulators to submit Comcast to the same lengthy scrutiny it received. Some competition lawyers think the Comcast offer is easier to approve and could gain clearance relatively quickly.
Murdoch first tried to buy up Sky in 2010. The deal collapsed when the phone-hacking scandal at the News of the World emerged, sparking criminal trials.
Roberts, the chairman and chief executive, said in a statement: “Sky has a strong business, excellent customer loyalty, and a valued brand. It is led by a terrific management team who we look forward to working with to build and grow this business.”
He added: “The combined customer base of approximately 52 million will allow us to invest more in original and acquired programming and innovation as we strive to deliver a truly differentiated customer experience.”
Comcast has bankers from Robey Warshaw, Evercore, BAML and Wells Fargo working on the deal.