Can be demonstrated by listening to Lord Lee. He is the famous FT columnist who was apparently one of the first to become an ISA Millionaire in 2003. You can listen to him give an update in this FT Money Show Podcast in which he reveals that his portfolio is now apparently worth £4.5m.
Interestingly £1m to £4.5m over 12 years from 2003 represents a reasonable but achievable 13.4% per annum by my reckoning, so maybe this can be an encouragement to everyone to make the most of their ISA allowances and let compounding work its magic.
Apparently there was also an article based on this in this weekends FT, although I didn't see that and can't find it on line so if any reader has a link or knows where to find it perhaps they could be so kind as to add it in the comments, cheers and don't forget to Compound that income.
Well the reason I couldn't find the article is because it was in today's FT not last weekends.
Having read it, it seems he did put a bit more capital in after 2003 which would make the compound return a little lower than the one I calculated above. It also included details of his current holdings and an extract from his book, How to make a million slowly, of his 12 Golden Rules.
So it is quite an interesting article and you should be able to read it on line here, although you may have to sign up as a user to access a limited number of stories for free each month, if you are not already a subscriber.