Martin Lewis reveals little-known code that could save you £600 on bills

And the first involves texting "info" to 85075 to find out if you're out of contract and free to leave without paying a charge.

He went on to explain that if you are out contract, there's four extra steps you can take to save money.

The first involves getting hold of a cheap SIM to put in your existing handset.

He explained how you're more likely to get a cheap SIM on a comparison website compared to going to your provider direct.

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The second step is checking what network you want to set up the new SIM with.

He said there are four main providers in the UK and every other provider "piggybacks" off them.

In other words, you can find out who else runs off the same network as your provider and find the cheapest contract out of all of them.

The next step is texting "PAC" to 65075 to retain the same number.

And the fourth step is to haggle with your current provider for a better deal, if you want to stay with them.

If they refuse, you can be put through to the customer retentions team and say you will consider their offer in the hope they come back with a better one.

One audience member told Martin she was paying £65 a month for her mobile phone contract.

But he mentioned one particular deal with Three where you get 100GB of mobile phone data for £15 a month - £600 less a year.

So shopping around for the best deals is well worth your time.

It came after Martin explained how mobile phone bills are set to rise by roughly 17% from next month and the "likelihood is you are paying way too much" if you are out of contract.

He said: "April price hikes will be peeing down on the nation's bank balances.

"Around the beginning of April, many mobile bills are to rise up to a typical 17%.

"And that's RPI inflation from last December with 3% on top, even if you are mid-contract, which is something that should be stopped.

"It's not always this - different contracts have different rises."

How else can I save money on a mobile?

If you're not sticking with the same handset and replacing your SIM and are looking to buy a new phone, you don't have to splash the cash.

If you only need the handset to make calls and text, you can get cheap ones for as little as £20, whereas top of the range models can cost you over £1,000.

If you are buying a new handset, you can either get one outright and then take out a cheap SIM-only deal, or get a bundled contract where you pay off the handset monthly.

Although it's worth noting you won't always get the cheapest deal on a bundle-only package.

It's always good to shop around for what's out there.

Meanwhile, carefully think about how much phone data you want in your contract.

Even if you use streaming services like Netflix and Spotify on a regular basis, you're likely to only need around 20GB a month.