Brits who are still with British Gas and British Telecom could see their bills rise over the coming months.

BT has increased the cost of its line rental by five per cent for those on the Together Option 1, making the cost of calls that little bit more expensive.

Jon Miller, director at independent comparison service uSwitch.com, said: "This is a real blow for BT’s customers. With most of their competitors reducing their line rental costs, BT customers can feel justifiably aggrieved at having to pay extra while seemingly receiving nothing in return."

British Gas' owner Centrica has also warned that the price of gas for domestic use will rise in 2006.

Tim Wolfenden, senior product manager at uSwitch, added: "Today’s announcement is not good news for the millions of British Gas customers that are still reeling from September’s price rise."

He continued: "The company is laying the blame squarely at the door of wholesale gas price rises which have risen by 40 per cent in the last three months. However, although Centrica predicts that other suppliers will also find it necessary to raise prices, British Gas still remains £58 more expensive on average than its competitors who have all been hit with the exact same wholesale price increases."

But with many companies now offering cheaper prices for the same service, uSwitch is advising customers to hunt around for the best deal and change to a more cost effective provider.