Brokers were given an indication of the power of the internet this week when online intermediary Screentrade promised it will not be beaten on price.

Screentrade, a subsidiary of software giant Misys, says it will refund customers the difference if they manage to buy any of its policies more cheaply from another broker.

It represents a serious challenge to brokers at a time when rates are rising, particularly in the hard-pressed motor market.

Paul Charles, editor-in-chief of the internet broker, said: "We are adamant we cannot be beaten by any other broker on price. If a customer finds a standard policy costing less than any offered by the 22 insurers on our website, then we will refund the difference in cost."

Charles said the pledge was meant as a serious challenge: "What we are saying to customers is 'go and search the market yourself and see if you can find cover more cheaply than ours'."

He also revealed that the online intermediary is currently seeing its sales increase by around 35% a month.

He said Screentrade's price pledge was similar to a guarantee given by department store giant John Lewis, which boasts its products are "never knowingly undersold".

The internet broker has made price comparison easy for its online customers by providing electronic links to its competitor insurers' websites.

More than 50 motor, household and travel products, provided by 22 insurers, can be accessed at Screentrade's website.

Screentrade is not the first broker to make a pledge on price, although it is thought to be the first online broker to do so.

For the past two years, Barclays' direct insurance arm has said it will also beat any quote offered on renewal, although this only applies to motor insurance.

The bank, which has 60,000 insurance customers, underwritten by Privilege Insurance, said its guarantee does not, however, include the promise of a refund if a customer finds a cheaper quote.

Mike Williams, chief executive of Biba, is however dismissive of Screentrade's promise on price.

He said: "At a time when most of the market is actively attempting to increase insurance rates and returns, Screentrade's offer does look like a price gimmick."

He added that, anyway, only a small proportion of insurance is sold on the internet.