Virgin Media O2 will bring through the steepest price hikes of any major broadband provider, or hit customers with sky-high exit fees if they want to leave mid-contract.
The two service providers will increase prices by 8.8% for both mobile and broadband contracts in April as part of an annual hike which adds together inflation in February (4.9%) with an extra 3.9%.
Mid-contract customers could face fees as high as £690 if they decide they want to leave.
Which?, the consumer-focused organisation, and Ofcom, the telecoms regulator, have both highlighted their criticisms of inflation-linked price hikes, arguing they are causing customers harm.
Rocio Concha at Which? said: 'Virgin Media and O2 customers face a lose-lose choice between huge price hikes and crippling exit fees.
“This comes on top of up to 17 per cent increases faced by some O2 customers last year - few would have anticipated such steep price rises when they signed up.
“Telecoms firms must do the right thing and immediately scrap these rises, rather than cynically taking the opportunity to cash in one last time at the expense of their customers before new rules take effect.”
In December, Ofcom proposed a ban on inflation-linked mid-contract price rises.
Ofcom said telecoms customers must be told upfront in pounds and pence about any price rises their provider includes in their contract, under new consumer protection plans set out today.
A Virgin Media O2 spokesperson said: “Which?’s own analysis shows that we continue to offer excellent value, with cable customers paying an average of just 10p more per day, and mobile customers facing an effective average increase of just 5p a day, for services they’re using almost constantly.
"This is further backed up by recent independent analysis which found that the cost of telecoms services has fallen by a fifth since 2017, while at the same time speeds and usage have increased significantly.”