A quarter of adults in the UK now use four screens, according to Trevor Vagg, Kantar Media Custom.
Speaking at the opening session of the Westminster Media Forum Keynote Seminar TV convergence: multiscreens, connected TVs and secondary rights, he added that 32% of adults in the UK now have tablets, or double the total a year earlier, with the figure rising to 43% in those in the 16-44 age group.
Significantly, 70% of adults shared their tablets with at least one other person, though only 7% used them outside the home.
Smart TV ownership, on the other hand, has risen from only 12% to 15% in the UK in the last year, and of those with a set only 53% plan to connect it to the internet.
Regarding on demand, viewing remains most popular through the TV set, with one third having watched through a TV set-top box in the last month.
Smartphones, on the other hand, were only used by 4% of viewers.
Vagg also said that public awareness of such services as Netflix and Lovefilm is increasing and a growing number of adults are willing to pay to watch content on a pay-as-you-go basis on any device.
In addition, he said that 42% of adults as a whole use the internet whilst watching TV, with the figure rising to 67% among four-screeners.