This report on European Social Values encompasses a wide range of metrics.
According to page 19, 81% of Europeans believe that "people like them" have too little influence in government and only 34% know how to get their voice heard. The figures for the UK are 77% and 31%. Switzerland, reknown for its direct democracy, scored 65% and 46%. Surprisingly a whopping 67% of the Dutch know how to get their voice heard in politics.
This is particularly relevant to Interactive Democracy as a central tennant is empowerment.
From the same page, 75% of Europeans thought "People should involve themselves in politics and current affairs". 73% of Brits and 79% of Swiss agreed. On this metric Sweden came out top with 91%!
Overall the figures suggest the majority want more political power but don't know how to get it. Another observation is that political access is higher in the Netherlands, Finland, Sweden and Denmark than in the direct democracy of Switzerland, but I don't know why. Perhaps public meetings disempower while secret ballots free the individual from social pressure? In Interactive Democracy, voting from your PC may help to solve this problem.