Sky has said it will shortly start registering interest from customers wanting to join its upcoming Sky Mobile service, as it prepares to take on BT and operators such as Vodafone in the £15bn UK mobile market.

In January 2015, the company reached a deal with O2 to launch a mobile offering, expanding its business from TV, broadband and home phones. It will begin registering potential customers from 31 October.

Stephen van Rooyen, the chief executive of Sky UK and Ireland, said: “We have long had eyes on the size of the prize. With £15bn in revenues, it is our largest adjacent sector for us. The opportunity to enter and take share is substantial. There are literally millions of customers for us to go after.”

Earlier this year, BT, which started taking on Sky’s pay TV dominance in 2012 by spending billions on sports television rights, including the Premier League, paid £12bn to buy EE and return to the mobile market.

Sky Mobile is expected to focus on getting its 12m existing subscribers to take up the mobile service.

“From a huge amount of research, we know that two-thirds of our customers, after being shown our proposition, would consider switching to Sky,” van Rooyen said. “Combined with our track record of selling more to our customers, mobile is an opportunity of real scale.”

Mobile is a key market for additional revenue and profit growth for Sky, which along with BT paid more than £5bn for Premier League rights last year, a 70% increase on the previous deal.

Sky will be hoping to emulate the success of its move into broadband, which has seen the company attract more than 6m customers since 2006, second only to BT.

Van Rooyen said the mobile service was being launched with a “limited and controlled capital investment”. Under the deal with O2, he added, Sky retains the “flexibility to switch to an alternative network provider, which ensures our economics remain competitive over time”.