Vodafone is set to slash its U.K. rates for mobile broadband as it looks to combat falling returns from mobile phone calls, and take advantage of rising numbers of people using their mobile handsets to go online.

From Monday, Vodafone U.K. will halve its monthly tariff for wireless data cards from £30 ($60) to £15 for a promotional period for consumers, which puts it on a par with mobile operator 3, which used to offer the cheapest data roaming rates in the U.K.

Customers wishing to take their laptops abroad can roam for just £9.99 per 24-hour session with Vodafone Connect Abroad in selected countries. For occasional Internet users Vodafone U.K. will introduce a 30-day no commitment plan - Mobile Broadband 30 Day - for just £20. Download limit is 1GB.

For business customers, Vodafone U.K. said its monthly fair usage on its newly named Mobile Broadband Business and Mobile Broadband Business Travel plans, would rise from 3GB to 5GB per month (with free USB modems).

"The concentration of Vodafone U.K. in the past has been on offering good value voice bundles," a Vodafone spokesman told Techworld. "The U.K. is a highly competitive market, but increasingly people are using their phones for data, and that it is now our area of attack."

Vodafone has already upgraded its 3G network in the U.K. to HSDPA (effectively 3.5G). Over 80% of the population has access to the 3G network, but the other 20% will have to use GPRS.

A modem will typically cost approximately about £40 depending on package, and is compatible with Vodafone's fastest speeds of 7.2Mbps (mostly in London and airports). However more typical speeds will be up to 3.6Mbps down (for receiving files) and 1.44Mbps up (for sending files).

The overall Vodafone group is currently averaging about £2 billion per year from data roaming and the operator has 25 million subscribers in Europe using 3G devices, which represents 20% of Vodafone's customer base. With falling returns from voice revenues, Vodafone is banking on data roaming to make up the decline.

"Voice returns have declined," admitted a Vodafone spokesman, "but voice usage has also gone up."

"This is well recognized, but this decline is being replaced by the uptake in data services," he added. "In particular our modems and mobile data cards are selling well."