The Competition and Markets Authority (CMA) waved through the deal following an in-depth investigation, concluding that concerns customers to see price hikes from the telecoms deal were unfounded.
Officials had provisionally cleared the deal last month and on Thursday confirmed the tie-up, which was first announced a year ago.
Investigators concluded that the costs of leased lines are only a relatively small element of rival mobile companies’ overall costs, so it is unlikely that Virgin would be able to raise leased-line costs in a way that would lead to higher charges for consumers.
They added that competitors in the market offering the same leased-line services, including larger rival BT Openreach, would keep competition healthy.
Why are Virgin Media and O2 merging?
Virgin Media owner Liberty Global, owned by John Malone in the US, has wanted to get the business ready to cope with the new 5G world for its mobile customers.
O2 is the UK’s biggest mobile phone operator with around 36.6 million customers across its networks, which also include giffgaff, Tesco Mobile, Sky Mobile and Lycamobile.
Virgin Media has around 5.3 million customers.
The deal brings together two of the biggest broadband and mobile phone operators in the UK a year after plans were first revealed.
At the time the deal was announced, the companies said it would create a “full converged platform” for customers, and will mean an investment of £10 billion in the UK over the next five years.
What does this all mean for you and your phone and home broadband bill?
Virgin Media and O2 customers will be able to access 5G
Customers who haven't been able to access 5G before may now be able to.
Virgin Media struck a deal with Vodafone to use their 5G network so that their customers don't miss out.
This means that new O2 customers from the merger will also have access to this.
More options for SIM only deals
Virgin Media will want to keep their existing broadband and TV customers away from rival suppliers like BT for other services, so this could mean more deals when customers move their SIM-only plan or pay-monthly phone contract in-house.
Customers could get cheaper bills and better deals
Usually, buying your mobile and home broadband from the same supplier should be cheaper.
Customers who have phone contracts, television, and broadband with three different companies could save money if their provider is all in one place – making their direct debits simpler.
There will be exclusive deals the two companies will be able to offer, which could include offering cheaper access to Virgin Mobile TV streaming content on your phone.
The CMA was initially concerned that, following the merger, Virgin and O2 could raise prices or reduce the quality of these wholesale services, or withdraw them altogether.
But the CMA confirmed last month the merger is unlikely to lead to any substantial lessening of competition.
Do customers need to do anything right now?
No. Nothing has changed for O2 or Virgin Media customers and they do not have to take any action right now.
Once the deal is completed next year, they are likely to start seeing more offers comprising broadband, pay-TV and mobile plans from across the two firms.
EE and BT customers have seen similar offers since the two merged in 2016.
What has the CMA said?
Martin Coleman, the chairman of the CMA inquiry, said: “O2 and Virgin are important suppliers of services to other companies who serve millions of consumers.
"It was important to make sure that this merger would not leave these people worse off.
"That’s why we conducted an in-depth investigation.
"After looking closely at the deal, we are reassured that competition amongst mobile communications providers will remain strong and it is therefore unlikely that the merger would lead to higher prices or lower quality services."
The CMA said at the outset of the investigation that it was not concerned about overlapping retail services such as mobile, due to the small size of Virgin Mobile, but instead focused on potential wholesale services concerns.