The increasing number of users taking advantage of the BBC's iPlayer catch-up service could threaten the licence fee, according to a new report.
Writing in the Times, Steven Swinford has highlighted a section of viewers who now prefer to watch programmes an hour later online, negating for a TV licence.
A possible problem could also be faced, Mr Swinford said, now the BBC has started streaming its channels live over the internet.
Although a licence fee is in theory required to take advantage of this new service, there is little or no way of detecting users without one.
Mr Swinford said: "While live shows do require a licence, broadband suppliers and politicians have warned that the corporation will not be able to catch evaders.
"The broadband companies who deliver the content say the technology does not enable the BBC to identify who is watching the shows, making enforcement virtually impossible."
Meanwhile, HDTV News has recommended the use of a digital media adapter in order to stream content from home network to television set.