Comcast said Wednesday that it's offering $31 billion to buy the British TV provider Sky, officially starting a bidding war between the U.S. cable giant and 21st Century Fox, which has offered $16.5 billion for the company.

But why is a U.K.-based television company such a sought-after piece of property, and what could a deal mean for Comcast's customers?  

The answer can be found in Comcast chief executive Brian Roberts's remarks to investors on an earnings call Wednesday morning.  

“It's a unique asset,” Roberts said. “It fits well with the assets we've already got. ... a benefit is, you'd get new geographies and additional scale that gives you optionality.”  

In other words, a deal would give Comcast access to a bigger overseas audience and — according to industry analysts — new TV programming.  

Sky is one of the United Kingdom's biggest broadcasters. It delivers programming that includes sports and crime thrillers. It has said it plans to spend more than $9 billion on content this year. Among its most successful TV series is “Riviera,” a drama starring Julia Stiles, who plays an art curator seeking to unravel the mystery surrounding her husband's death.