France could disrupt television viewing for thousands of people in Britain by beaming high-powered digital signals across the Channel, a public spending watchdog has warned.
The National Audit Office said once France achieved its digital switchover there would be a risk of interference with the digital terrestrial signal in parts of southern England.
The programme to replace the UK's existing analogue television network with a fully digital network is scheduled to be completed by the end of 2012. The French deadline is November 2011.
It said: "On current timetables there is a risk that once France has achieved digital switchover there may be interference with the current digital terrestrial signal ... as a consequence of high-powered digital transmissions from France."
The NAO said independent broadcasting regulator Ofcom was leading negotiations with the French to coordinate programmes and minimise the risk.
But it pointed out any decision to bring forward the digital switchover timetable, for example to avoid such interference, would result in some extra costs for the BBC.
The BBC considers that such changes to the timetable are "unlikely", but if that did happen it would want compensation from the Government.
Britain's own digital switchover is being led by the "flagship" area of Copeland in Cumbria, where 25,000 households in the town of Whitehaven and the surrounding borough of Copeland have just had their analogue channels switched off.
Richard Ashworth, Conservative MEP for the South East of England, said he had written to the European Commission raising concerns about the schedule for the switchover to digital television in France.
He pointed out that there was a possibility of interference with analogue as well as current low-power digital television in southern England.
The MEP has asked the European Commission to investigate and coordinate the switchover between France and the UK to prevent interference. ( Sky )