Internet service provider (ISP) Virgin Media has raised fresh objections to Project Canvas, the scheme geared at providing IPTV services to UK homes via set-top boxes.

The firm says the return of Channel Five to the initiative – which also includes Channel 4, BBC and ITV, plus broadband providers BT and TalkTalk – raises significant cause for concern.

Virgin Media, which has previously warned about the competition issues raised by Project Canvas, is now calling for a full, independent investigation.

A spokesperson for the ISP commented that with the return of Five, the Project Canvas joint venture partners represent "an even greater concentration of all TV viewing".

"This reinforces the pressing need for a thorough and independent examination of this closed, anti-competitive platform," the source said.

"We're all already paying for this, whether we want it or not, so we urge Ofcom to bring some much needed transparency to the whole collaboration."

Channel Five left the project earlier this year, but under the new ownership of Northern & Shell, has now returned to the fold.