Why is the FTSE 100 important?

The FTSE 100 is the index of the UK's largest 100 companies, and is a key indicator often referred to by financial experts.

It has performed very well in 2013, despite the economic troubles, rising by over 6% in January.

But why does this matter to everyone else not working in the financial sector?

The BBC's Steph McGovern has been finding out.