Mobile phone firms will soon have to let users cap their monthly bill to stop them being hit with unexpected charges for going outside their allowance, after a new law was passed.

The Digital Economy Bill, which received Royal Assent on Thursday (28 April), will mean both new and existing mobile phone customers will be able to ask their provider to set a monthly limit on their bill, and they won't then be charged more than this amount.

While the new law was rubberstamped yesterday, as yet there are no further details on how or when it will be put into place. The Department for Culture, Media and Sport has said it will now begin working with providers, but further details will not be finalised until after the June election.

'A big step forward' to tackle mobile phone debt

It's hoped the new measures - which are likely to benefit both pay-monthly and Sim-only users - will help stop people running up huge unexpected phone bills.

Citizens' Advice, which has long campaigned on the issue, says it helps 40,000 people per year who are in mobile phone debt. It says 54% of people have received a higher-than-normal phone bill in the last 12 months.

It dubbed the move a "big step forward" but said there is still more to be done to protect consumers.

How to prevent 'bill shock' BEFORE the new law comes into effect

Some providers already allow you to cap your bill - for example, Tesco Mobile allows customers to set a limit of between £2.50 and £40 above their normal monthly allowance.

So if you're worried about going over your allowance, check with your provider to see if it will already allow you to set a cap.

If not, you can check your current usage and see where you are overspending, then try these tips:

  • Use Wi-Fi wherever possible
  • If you really need more, ask network about upping your allowance – weigh up whether it will cost less than exceeding your limit and you can try to haggle
  • Check if there are any apps you have which are eating up your data allowance

See our 30+ Cheap Mobile Tips for full help on how to cut your mobile bills.

Mobile users to be able to set monthly cap on charges to prevent 'bill shock'
Mobile users to be able to set monthly cap on charges to prevent 'bill shock'