Once again, past performance is no guide to future returns.
A fool and his money...
Maybe a bit harsh ?
Not harsh at all.
Only invest what you can afford to lose. I know someone who one day his portfolio was worth £120K. The next morning it was only worth £20K. It happens, and as Clubman says past performance is no guide.
Unfortunately many people haven't lived with a stock market or house price crash. This leads to a lot of them being totally naive. It's not if it might happen, but when it will happen. Many in UK/Ireland are in credit up to their eyes. The bubble will burst. Might be tomorrow, might be in 2 years, but it will burst.
So, I wouldn't borrow anything to invest in shares.