Millions of mobile and broadband customers face price rises of about 8% after the shock increase in inflation in December.
Most of the main operators have bill rises written into contracts that are linked to the consumer prices index (CPI) measure of inflation for December. Typically the increases are CPI plus 3.9 percentage points, which means price rises of 7.9%.
The increase is lower than last year, when the practice led to rises of up to 17.3%, which the Guardian highlighted risked fuelling the cost of living crisis.
It could also be the last time that inflation is used in operators’ calculations, as in December the regulator, Ofcom, proposed banning index-linked rises, saying they were too confusing for consumers.
On Tuesday, BT become the first big telecoms company to scrap the inflation-linked price rises for mobile and broadband customers, although not before pushing through a final increase this year.
Its customers will pay 7.9% more from April.
Vodafone and Three have both confirmed that they will pass on rises outlined in current contracts, which also means a 7.9% rise this year.
Vodafone said the change would affectabout half of its customers, who could expect an increase of “a few pounds a month”.
Three said the average price rise was less than £1.50 a month.
A Vodafone spokesperson said: “We know no one likes to see prices rise, but, like all industries, we face inflationary pressures that raise the cost of running and investing in our network.”
They said the company supported Ofcom’s work, and added: “We have a strong presence in the non-contract market which doesn’t see price rises, and our support of vulnerable customers won’t change – we freeze prices for those registered as financially vulnerable and for those on our mobile or broadband social tariffs.”
Other mobile companies have not yet announced whether they plan to go through with the increases.
The consumer group Which? said it would be “completely unacceptable” if providers went through with inflation-linked rises.
Rocio Concha, the director of policy and advocacy at Which?, said: “This announcement could trigger a new wave of price hikes from big broadband and mobile providers – just 12 months after many firms imposed price increases of more than 14% on customers.
“It would be completely unacceptable for providers to follow BT and inflict another above-inflation increase on customers after Ofcom proposed banning this practice, saying it causes substantial consumer harm.
“Telecoms providers must step up and do the right thing by immediately scrapping any plans to hit their customers with above-inflation price hikes this April.”
Virgin Media bases its increases on the typically higher RPI inflation rate and uses January’s figure.
