Vodafone has announced that this summer it will begin a multi-million pound investment to extend its fast 7.2Mbps mobile broadband network to a further three million people across six major conurbations: Birmingham, Bristol. Glasgow, Liverpool, Manchester and Reading.

These towns and cities join London and major British airports, which were the first locations to benefit from Vodafone's high speed upgrade in 2007.

This follows the news that rival mobile operator 3 has filed an official complaint with the Advertising Standards Authority against Vodafone about its claims for mobile broadband speed.

3 have complained about a Vodafone ad stating that their mobile broadband offers 7.2Mbps speeds, and not being clear on the geographical restrictions.

Perhaps in response to this, Vodafone has also announced that customers will "see a change in the way Vodafone UK sells Mobile Broadband" with more info at the point of sale to help them understand the time it will take to download files, films and music on the mobile broadband network.