BT has announced an updated mobile broadband service for smaller businesses, offering a USB stick which uses Vodafone's HSUPA network.

BT Business Mobile Broadband is available as a standalone option costing £17.50 + VAT per month, but the telco has an offer running until the end of this year which provides the service free for firms signing up to option 2 or 3 on BT's Business Total Broadband package for 24 months.

Options 2 and 3 cost £26.99 + VAT and £40.50 + VAT respectively, and offer fixed-line access and BT Openzone access with 2,000 free minutes.

Options 2 and 3 provide 1GB of data over the Huawei Mobile Connect E170 HSPA USB device per month, and 2,000 minutes when connected to BT Openzone Wi-Fi hotspots. Firms will be charged £12.50 + VAT when the minimum sign-up period expires.

If the 1GB mobile data cap is breached firms will be charged at 10p per megabyte downloaded, and 10p per extra minute if they overrun the 2,000 Wi-Fi minutes limit.

The standalone BT Business Mobile Broadband service has data rates capped at 3GB. Customers will be contacted first if the limit is breached before charges apply.

BT Business Total Broadband option 2 offers a free router, an anti-virus and anti-spam package and 24/7 freephone support. Option 3 adds BT's Internet Security Pack for five PCs, and IT Support Manager allowing remote troubleshooting from BT's IT staff.

"Fixed operators need to come up with strategies for dealing with a rapid and invasive expansion of mobile broadband into their core growth area of consumer broadband," said Rupert Wood, a principal analyst at Analysys Mason, in a new report.

The report forecasts that 47 per cent of European broadband users will use mobile broadband networks and that nearly a quarter of broadband-equipped sites will use mobile-only.

"Nearly half of fixed broadband users currently have a usage profile that is no higher than the average usage on mobile broadband, making the size of the addressable market for mobile broadband as a substitutive consumer proposition enormous," said Wood in the report.

One of the potential problems for mobile network operators in keeping the momentum going is that they need to "dissociate rises in network costs from the exponential increases in bandwidth demands" that have already been seen, according to Wood.

"This will involve access network upgrades, but also, crucially, the transformation of legacy backhaul to an aggregated IP infrastructure," he said.

BT holds an advantage in this respect, since Vodafone signed a five-year contract with BT in April to manage network connectivity between Vodafone's base stations and its core network.

Earlier this month BT signed a similar contract with Vodafone competitors 3 and T-Mobile.