Media mogul Rupert Murdoch leaves his home in London, Britain March 4, 2016. REUTERS/Stefan Wermuth

LONDON (Reuters) - Rupert Murdoch is unlikely to offer any new concessions to protect the editorial independence of Sky SKYB.L, increasing the chance that the $15 billion takeover deal goes to a lengthy investigation, a person familiar with the situation said.

Murdoch's Twenty-First Century Fox FOXA.O was dealt a blow last month when Britain's media secretary, Karen Bradley, said she was persuaded that the deal could give the Murdochs too much influence over the media, after regulator Ofcom assessed the impact of the transaction.

Murdoch also owns the Sun and Times newspapers in Britain.

Bradley said she would make a final decision on July 14, giving some investors hope that Fox could avert a full investigation if it offered concessions to protect the editorial independence of Sky’s 24-hour TV news channel, Sky News.

A person familiar with the deal said however the company was unlikely to offer any new remedies, opting instead to let the competition watchdog examine the deal.

Murdoch, 86, and his family have long coveted full control of Sky, despite the damaging failure of a previous attempt in 2011 when their British newspaper business became embroiled in a phone-hacking scandal which forced them to abandon that bid.

Britain’s political leaders have long sought the backing of Murdoch and his newspapers and any attempt to expand his media empire in the country sparks intense political scrutiny.

Rupert’s son James, who is chief executive of Fox and chairman of Sky, said in March that worries about his family exerting too much power were unfounded in an era of online providers such as Facebook, Buzzfeed, Netflix and Google.

Fox has said any referral for an in-depth probe could mean the deal would not close before next June. Both Sky and Fox declined to comment.