I just came across a YouGov poll from the summer of 2014 which asked respondents,
Thinking about the British Empire, would you say it is more something to be proud or more something to be ashamed of?
A full 59% of respondents said "more something to be proud of", while only 19% said "more something to be ashamed of". Young people were slightly less sanguine than old people, and the Scottish were slightly less sanguine than the English; but there was no subgroup in which more people felt ashamed than felt proud. The poll also asked respondents,
Overall do you think the countries that were colonised by Britain are better off or worse off for being colonised?
49% of respondents answered "better off", and only 15% answered "worse off". Interestingly however, when asked, "Would you like Britain to still have an empire", only 34% said yes, while 45% said no.