Mobile operators have been told to reduce the cost of sending texts and accessing the internet from abroad or face the prospect of further regulation.

The European Commission has said that the cost of using the internet on a mobile while travelling is "too high", and has called on operators to abandon their charges or be forced to reduce their rates.

On average, British travellers pay £4.11 per megabyte of data - about enough to view 200 web pages, as compared with paying £1.50 while at home. Sending a text from a European country can cost as much as 49 pence.

Viviane Reding, the European Commissioner for the Information Society and Media said that the "horror" of getting "terribly expensive bills" had been the main barrier preventing consumers from using the internet on their phones, and called on the industry to introduce tariffs which would make the web "as open and easy to use" on a mobile as it was on a computer.

The Commission has already forced carriers to lower the cost of making phone calls while travelling in Europe, as a result of which so-called "roaming" fees have been halved.

Addressing a mobile industry conference in Barcelona, Ms Reding said: "Sending text messages or downloading data via a mobile phone while in another EU country should not be substantially more expensive for a consumer than sending text messages or downloading data at home. Higher retail charges abroad must be justified by additional cost of operators, or they will have to disappear."

In particular, Ms Reding was suspicious of the wholesale tariffs which operators charged one another to allow access to their networks, and called on national competition regulators to be vigilant.

"While I hear on the one side about wholesale tariffs of up to €7 per megabyte, I have also learnt with interest of some of the wholesale deals that are being negotiated on a voluntary basis – for example 25 euro cents per megabyte," she said. "This certainly indicates that there is a lot of commercial scope for substantial reductions over the average rates that are quite common today."

She called for the introduction of more flat rate services - so-called "all you can eat" packages where consumers pay a fixed amount for unlimited access to the internet on their mobile each month – and said existing services of this type were still too expensive.

"For European consumers this is clear, this will be the future. The only question is for the European industry, how quickly will you make this transition? The slower industry is to react the more painful and difficult will be the transition to open platforms and flat-rate billing."

Several operators, including O2, Vodafone and 3, have already lowered the cost of accessing the internet while abroad.

Tom Phillips, head of head of Government and Regulatory Affairs at the GSM Association, the mobile industry body, said: "Accessing the internet and web pages while you're roaming around Europe using a mobile phone can be expensive. But it's a very new service, it's growing in popularity and the prices are coming down very quickly."

Ms Reding gave operators until July to reduce their charges, or said the Commission would again propose "regulatory intervention". In June last year, the Commission introduced the EU Roaming Regulation, as a result of which the cost of making a call while abroad is capped at 49 euro cents per minute.

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