Brookmead Consulting has revealed the findings of an extensive survey following up the influential piece of research it published on telemarketing and unwelcome calls in 2005.
It predicts that numbers registered with TPS will rise from 14.7m in June 2008 to between 16m and 17m in 2014.
But it warns that more mobile numbers will be registered with TPS if there is growth in the trend of people receiving voice and text marketing on their mobiles, which is driven by the falling cost of the activity. A million of the current 14.7m TPS total are mobile numbers.
"Telemarketing calls to mobiles are starting to become an issue for some people," according to Brookmead.
It also claims that the issue of silent calls is still not resolved, though the number of such calls received by the average person has fallen from 9.6 per month in 2005 to 2.1 per month in 2008, and people are now less worried by silent calls because they understand the phenomenon better.
The paper argues that people's tolerance of telemarketing has been eroded by mis-selling and scams. This combined with the larger factors of the extent of TPS registration and the costs of complying with new regulations has resulted in companies scaling back the amount of cold calling they are doing.
It also warns that affinity telemarketers - third parties who are allowed to sell to an organisation's customer list - are concerned that consumers' increasing awareness of identity theft is making them reluctant to hand out personal details.