As was mentioned previously in the thread, if you buy and hold and don't sell your investment (i.e. house, stocks or whatever the hell you want to invest in) when the economic bubbles burst (housing prices crash, stock markets fall), 6% is very achievable over the long run and I think you will find a conservative figure, the fund I linked to previously returned 11% annually for the last 3 years, granted this will not happen year on year, as some years the return is much worse (i.e. recession in 2008), investments still return dividends, but their value falls with this, which is why we give the figure of rounded 6% return over a long term. Eventually when the economy recovers share values rise again and your no worse off than before the crash.
Yes, the markets will slow down at some point, but by avoiding selling your investments at fire sale prices (time of economic slowdown) you thereby eliminate almost all the risk, your capital keeps on growing regardless of how shitty the economy might be doing over one trading week every 7-8 years.
What we cant protect our investments from is the eventuality that the world economy spins into economic meltdown, all international trading stalls and we revert to the dark ages due to peak oil (if you believe in it?), I don't think your insurance company is going to be paying you out so both sides are losers. But that's another story.
Time for some homework
@srw , go find out for me how much the global markets have grown since 2008 (the last crash), then come back and state that I am delusional.
For those worrying about the utility of their cash, if it takes you more than a few months to save up £1500, this strategy will never be for you. Why? Because you are enjoying the utility of your money too much to gain from it in the long term, that's the trade off.