Customers of O2 and Virgin Mobile will soon see their bills hike up to 11.7 percent.
As the cost of living crisis continues, the Mirror reports that some pay monthly customers will see their bill rise by an extra £48 a year.
This comes after O2 and Virgin Mobile merged last year.
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The pay monthly bill rise is another price increase following the news that energy bills are set to rise, as is National Insurance and as the rate of inflation goes up, so do food prices.
The increases will hit from April 1 - although the exact amount your bill will rise by will depend on the network you are on, your contract, and when you joined.
The increase is based on the retail price index (RPI) rate of inflation - which now stands at 7.8 per cent - plus 3.9 per cent.
An O2 spokesperson said: "We recognise price changes are never welcome, and always balance keeping our prices competitive with the need to continue investing in the services that our customers use and love.
"For most customers the price increase only applies to the airtime part of their bill and with our most popular tariffs costing from as little as 33p per day for super-fast data with unlimited minutes and texts, our customers receive incredible value as well as extra perks such as Priority."
How Virgin Mobile price rise will affect you
For Virgin Mobile customers, it will only affect your airtime tariff-which covers your data and calls and text allowance.
This means that all Virgin Mobile customers will see their bills rise in line with the full 11.7 per cent but payments for a handset will remain unchanged.
Someone with an airtime tariff that costs £7 a month would be charged an additional 82p per month. This works out at around £9.84 annually.
Virgin Mobile told the Mirror it wrote to customers back in January to warn them about the price hike.
This was a change to their terms and conditions and so did allow them the right to exit without penalty.
How O2 price rise will affect you
For those who join O2 after March 2021 will face the full 11.7 per cent price hike - adding as much as £48 a year to your bill.
If you joined before March 25, 2021, your price increase will be capped at just the rate of RPI inflation, which is 7.8 per cent.
Customers on an O2 Refresh tariff - where you have separate device and airtime bills - will only see the hike added to the airtime part of their plan.
O2 told The Mirror its customers don't have a right to cancel as a result of this price change, as it was all outlined to them at point of sale.
Ernest Doku, telecoms expert at Uswitch.com, said: "The idea of both Virgin Mobile and O2 customers' bills increasing by 11.7 per cent shows the absurdity of linking mid-contract price hikes to inflation.
"The networks both calculate price rises for most of their customers by adding 3.9 per cent to the RPI measure of inflation, which was revealed today as a staggering 7.8 per cent.
"These mid-contract rises are written into customers' contracts, but no one signing up for their deal 12 months ago could have guessed what their increase would be."
