Martin Lewis has called out Sky after pushing for more to be done to protect broadband and mobile customers in the wake of today's announcement of a new charter which bans additional mid-contract price hikes.

On Wednesday afternoon (February 11) the Department for Science, Innovation and Technology unveiled a new set of rules for mobile and broadband firms to follow which has been agreed to by major players including BT, Virgin Media O2, VodafoneThree, Sky and TalkTalk.

The rules mean that firms will not be able to announce extra price hikes on top of the ones already communicated to customers at the outset of a contract.

Last year, O2 sparked anger from campaigners like Martin Lewis when it announced a price hike on top of the price hike it had already told customers about, and gave them 30 days to cancel to avoid it.

The new charter of protections announced today promises to stop 'unexpected' mid-contract price hikes, though they still allow price increases mid contract.

The government said: "Under the commitments in the charter, customers will know exactly what they'll be paying when they sign up for a new mobile or broadband deal - with no unexpected price rises midway through a contract. Customers will be given clear information on any future price changes up front, so the price they sign up to is the price they can expect to pay."

But Martin Lewis took to Twitter to call out 'two glaring gaps' in the charter's protections, including one used by Sky.

He said: "The govt has today agreed a charter with the big broadband and mobile players - I've been told this is in part a response to the letter I wrote to the Chancellor about O2's price hike on a price hike. Here is my official quote...

"I am cautiously optimistic that the 'Telecoms Consumer Charter' is an improvement within the narrow range of issues it addresses. It should mean more people are aware of social tariffs, and we are less likely to see a repeat of O2's 'price hike on a price hike', where customers were told at sign-up how much prices would rise by mid-contract, only to be told later they would by hiked even more. That ran roughshod over Ofcom's supposed protections.

"Yet the Charter still frustratingly leaves two glaring gaps in Ofcom's flaccid rules unaddressed. Both effectively embed above-inflation mid-contract price hikes into the mobile and broadband system - the very mischief the reforms were meant to fix."

He added that the key issues in the charter are:

"1. Transparency doesn't stop price rises. Firms that follow the rules now simply have to tell customers, in pounds and pence, how much prices will rise by mid-contract. While that improves clarity, it does nothing to limit the size of the increase. In many cases, customers have seen bigger rises under this system than under the old inflation-linked model.

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"2. 'Variable pricing' remains a loophole. Sky continues to operate using a variable pricing structure, meaning customers can face mid-contract price changes, albeit with the right to leave within 30 days of notification. Yet in practice, many people only notice the increase once it hits their bill, not when the notification arrives - making that protection far less effective than it appears."

Martin added that it would be a 'simple fix' to correct it, by banning firms from above-inflation increases.

He said: "A simple fix... I don't understand why we don't grasp what is by far the simplest and most effective solution: ban firms from increasing prices above inflation during a fixed-term contract. Do that, and the job's done."

Technology Secretary Liz Kendall said: "Broadband and mobile customers deserve to be treated fairly and not face sudden jumps in their bills.

"Following action by this government, telecom companies have now agreed to end unexpected midcontract price rises and making social tariffs easier to access.

"These changes will make a real difference to millions of consumers across the country and help with the cost-of-living pressures."

Sky has been contacted for comment.