Net users would face a heavy bill if they had to pay for what they watch online
Sending letters to persistent pirates will not stop them copying, suggests research.
Only 33% of those receiving a letter from their ISP would stop pirating content, found a survey carried out by legal firm Wiggin.
However, it found 80% would stop if the letter were followed by action such as cutting net connections.
The finding comes a week before the release of a UK government report aimed at tackling web piracy.
The research, commissioned by media lawyers Wiggin, questioned more than 1,500 UK consumers about their changing digital media habits.
On June 16, the government is widely expected to publish the final version of the Carter Report.
Among the topics considered by the wide-ranging report will be recommendations that ISPs investigate "technical solutions" to piracy which could involve slowing down connection speeds for unrepentant pirates.
"A letter would not be enough," said Alexander Ross, partner in the media and technology group at Wiggin. "It does take an ultimate sanction."
Cash for content
The survey also found that there could be a lucrative market for ISPs if they did changed their flat rates for prices based on usage.
Keen consumers of video, online games would pay a premium to maintain their access to these sorts of content, said Mr Ross.
Media consumption habits are changing radically, suggests the research
Men aged 20-34 asked in the survey said they would pay £48 per month for such media. Women aged 25-34 would pay up to £39 per month.
On average, suggests the research, web users would pay £26 per month to keep access to their favourite firm of online content.
"The suggestion is that if ISPs develop content services of their own and tier their access there are ready and willing customers for it," said Mr Ross.
In line with the interest in web content, the survey revealed strong interest, 7% of those questioned, in watching them on family TV sets.
The appeal of this crossed age divides, found the survey, with 77% of males and 61% of women aged 45-54 keen to do so.
Also popular were on-demand TV services. Among those questioned, 46% said they were occasional and regular users of the BBC iPlayer. Up from 13% in 2008. Similarly, 4OD use was up from 16% to 28% and ITVPlayer up from 12% to 25%.
"The distinction between the sit back experience of scheduled broadcasting and the sit forward experience of on demand access is becoming ever more blurred, and consumers are driving the convergence," said Mr Ross.
However, 49% of those questioned said they thought it was currently too difficult to connect up a TV and PC to get at net content.
"Internet on the main television is set to become a mass market reality within a short period," said Russell Hart, boss of Entertainment Media Research which carried out the survey for Wiggin.
Though, he added, makers of TVs had to be sure their products were cheap enough and easy to use if this potential market was to be tapped.