Most TV viewing in households with personal video recorders such as Sky+ is still live and "traditional scheduled TV will be around for a long time yet", according to new research.
Viewers still paid attention to adverts even when they fast-forwarded through them, the study found.
The findings are likely to reassure commercial broadcasters and advertisers who have been worried that the rise of time-shifted viewing spells the end for traditional advertising.
"This research suggests that the impact of PVRs on viewing of commercials may not be as extreme as some had previously thought," said Mark Bunting, the strategy manager at media regulator Ofcom.
"Broadcasters undoubtedly face many challenges in this highly dynamic market but traditional scheduled TV will be around for a long time yet."
Patrick Barwise, of the London Business School, part of the consortium behind the research, said: "These results show the importance of measuring actual, rather than claimed, behaviour.
"People's self-perception is that they time-shift a lot and always fast-forward through the commercials. The reality is very different, more complex, and much less threatening for the future of TV advertising."
The study used in-home cameras and microphones to measure the TV watched by eight households of varying types.
It found that the "great majority" of viewing in PVR homes is live, in contrast with research in the US into "early adopters" of similar technology.
Most commercials in time-shifted viewing are fast-forwarded, the study found, but viewers "continued to pay a high degree of visual attention" and often engaged with ads while fast-forwarding at high speed.
Sue Moseley, of media agency Initiatve, said the study helped to show changes in consumer behaviour.
"Whilst new technology brings the opportunity for greater on demand media consumption, TV continues to have a significant influence on peoples' lives and therefore retains an important communication role for many brands," she said.
Full results from the study, together with findings from the US and data measuring Sky+ usage, will be revealed next month.
The consortium behind the study consisted of research consultancy ACB, the London Business School, Initiative, Ofcom, ITV, Channel 4 and Channel Five.
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