Broadband speeds are still posing a big problem for British customers, according to a new survey.

In a survey of 1,500 UK broadband users, mobile phone and internet company O2 found that a quarter of those questioned cited connection speed as the most frustrating thing about their broadband connection.

This was higher than the 20 per cent of respondents that complained about getting through to customer services and the 10 per cent that were concerned about security problems.

Just under half of those questioned also admitted to being unsure of the speed they were getting.

According to O2, these frustrations and uncertainties are caused by the “up to” clause used by many boadband ISPs.

Mike Fairman, head of broadband at O2, told Computeractive: “People are unhappy with the speeds they are actually getting, over the ones promised.”

He agreed with Computeractive's Crystal Clear Broadband, saying that “ISPs need to much more honest about these speeds”.

“People should not be booked onto a package they possibly cannot get,” he added.

O2 pledges to test each customer's phone line before recommending a broadband package. The ISP also claims to go a step further, testing the customer's line a month after the contract has been signed. If the speeds are found to be too low the company will move the customer to a cheaper package.

Michael Phillips of consumer website BroadBandChoices.co.uk agreed that broadband speeds are a problem, saying that "speed connections are one of the most infuriating things for a customer".

However, he disagreed that speed was the most important issue for broadband consumers, adding that "in our view, customer services that require customers to call premium-rate numbers are the biggest customer frustration".