The UK digital population for PC, mobile & tablet use is 46.2 million people

"The MMX Multi-Platform tool launched today shows the total UK digital population for PC, mobile and tablet use is 46.2 million people. Until now, ComScore has measured 44.66 million PC and Mac users, and 30.8 million mobile users, and is for the first time now reporting a UK tablet audience of 12.8 million people.
The product combines PC / Mac, tablet, and mobile browsing and app data and mobile wifi browsing and app data. It will add mobile and tablet app dwell time in the first quarter of 2013, with mobile and tablet video to follow in the second quarter.
Meanwhile the 55+ age group has a higher percentage of tablet ownership than the market as a whole and their use of smartphones has increased by more than 20 per cent year on year, according to the research.
However, it also revealed the post PC era is strongest for the 25-35 year old bracket with 86 per cent using multiple platforms or just mobile or tablet."
Source:  The Drum, 1st October 2013