The BBC's iPlayer is well into its public Beta phase and, despite controversy about operating systems the service works on, expects to have picked up about half a million users before it launches for real.

But, another row has broken out over the online video download service, this time involving Britain's biggest internet service providers.

An as yet unofficial group, seemingly led by Tiscali, BT and the Carphone Warehouse have apparently raised strong concerns over the iPlayer's filesharing functionality that could potentially mean bandwidth problems for UK broadband customers.

In theory, millions of users could sign up to the BBC iPlayer, which works on a peer-to-peer basis, which uses cumulative bandwidth of network members, putting a strain on the UK's internet networks.

Rumours suggest that these three big providers have met and are trying to get money from the BBC to help fund network upgrades and stop the corporation getting what has been described as a "free ride".

"The internet was not set up with a view to distributing video. We have been improving our capacity, but the bandwidth we have is not infinite", said Mary Turner, chief executive of Tiscali UK.

"If the iPlayer really takes off, consumers accessing the internet will get very slow service and will call their ISPs to complain."

If the ISP's demands are not met by the BBC, they may implement "traffic shaping" which is a way of limiting bandwidth, controlling the amount of customers who can access the iPlayer at any one time.