CK Hutchison, which is controlled by Hong Kong billionaire Li Ka-shing, is buying O2 from Telefónica, and will merge it with its Three network depending on regulatory approval.
In an interview with the Financial Times, Canning Fok, co-chief executive of the Hong Kong group, said the combined UK business would be run by David Dyson, Three's chief executive.
"David Dyson is our leader here and so he will be the leader [of the new business]," Mr Fok said.
This will raise questions over the future of O2 boss Ronan Dunne, although other roles could exist in the wider group. A spokesperson for Mr Dunne confirmed that he would step down from his position as chief executive of O2 after the deal had completed.
Mr Fok added that an initial public offering of the combined 15 billion pounds business had been discussed with external investors, who have committed about 3 billion pounds to fund the deal. Investors include the CPP Investment Board and Singapore's GIC.
O2 was last listed as a separate business after being split from BT in 2003.
"There is a liquidity requirement by our investor group and one way to provide will be an IPO, which we will support," said Mr Fok, who declined to give a timeframe.
"It's only reasonable that you give yourself some time. No one is a magician . . . you need to work on business and get the customer happy."
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He said the group would initially continue to use O2 and Three as brands. "You can assume that it might become Three. But there is a twist," he said. "We haven't made the final decision yet. We have a certain time we can use O2. It's a strong brand."
Mr Fok was confident that Hutchison would agree a deal with the regulators to pass his acquisition of O2 in the UK and the merger with Wind and Three in Italy.
Analysts have warned that both deals might face difficulties after a similar deal in Denmark was pulled this month in the face of opposition from the antitrust regulator in Brussels.
"This market is full of competition. We have done this exercise in Austria and Ireland and we will come up with a solution in which everyone is comfortable," he said.
Denmark was a different sort of merger to the UK, he said, given the attempt to merge the second- and third-largest groups, which could have led to a near duopoly.
He also said that he would talk to Ofcom, the UK telecoms regulator, about the future of a complicated network sharing arrangement. O2 shares a network with Vodafone, while Three shares with EE, but both rival groups would resist being left on their own in a three-company market.
Mr Fok said it would not be practical to offload the extra traffic on one network immediately.
"Three is 45 per cent of the data in the UK so it's not like one day I can make a decision to switch to this or that. We have to work with the regulator to see what is the best approach," he said.