Broadband and mobile customers will see an estimated £17.4 million per month added to their bills when mid-contract price rises come into effect on April 1, according to price comparison firm Uswitch.

Although the telecoms market has moved to a ‘pounds and pence’ model that declares flat rate annual price rises upfront, millions of Brits are still on older inflation-linked contracts that abide by older rules.

Official figures released today show the UK inflation rate rose to 3.4 percent in the year to December, which helps paint a picture of the unpredictable price rises these customers can expect later this year. Many service providers work out rises by adding CPI and a further 3.9 percent hike to reach a new total.

“Today’s CPI announcement is another piece of the puzzle in April’s price hikes,” said Ernest Doku, telecoms expert at Uswitch.com.

“For the estimated 8 million mobile and broadband customers still on older inflation-linked contracts, these increases will add an expected £17.4 million a month to household bills this spring.

“Following Ofcom’s rule changes, price rises are now split. While those who switched recently benefit from the transparency of fixed ‘pounds and pence’ rises, many of these newer hikes are actually proportionally higher than the current rate of inflation.

Ofcom’s new rules came into effect in January 2025, but many broadband and mobile contracts that predate that are still linked to inflation. Many telecom contracts enforce annual price prices that increase monthly bills. Given contracts typically last between 18 to 36 months, consumers can see bills rise substantially over time, even if they are receiving the same service.

On the newer rules, several broadband firms have announced flat rate £4 price rises for April 1, while mobile providers have set price rises at anywhere up to £2.50.

Doku said one way to avoid the price rises is to switch to another service provider. This is easier if you are out of contract, which means you have finished the initial term of your contract and are simply paying a monthly rolling fee – which could be lower if you switch.

“Consumers must be proactive to ‘reset the clock’ by switching to a new deal, as staying out of contract is more dangerous than ever,” he said.

“Even with a £4 monthly rise, switching is almost always cheaper than staying on an expired plan as compounding price increases can snowball year after year.

“If today’s announcement affects you, it’s more likely your contract is nearing its end date or has already expired. This means it’s likely you’re free to switch and save. If you’re still in-contract, set a reminder for your end date now so you can switch immediately and avoid paying costly out-of-contract rates.”

It is difficult to find a broadband service provider that does not increase bills annually, although Trooli and YouFibre offer fixed bills.

There are plenty of options for mobile providers. Mobile virtual network operators (MVNOs) lease network space from EE, O2 and VodafoneThree, often with cheaper prices and no annual price increases. These include VOXI, Lebara, Giffgaff and SMARTY.

Providers are now legally obliged to help you switch to a new firm, so don’t be afraid to take the plunge – it can save you money.