In reply to nikki_smilez:
I don't think you should reference it as though it was online - the fact you accessed it online isn't really relevant - you are referencing the legislation itself, the need to reference the link and accessed dates for web references are based on the changeability of web based references which aren't relevant to an act of parliament like this.
I think it should be:
1. Title of the Act including the date – underlined, or bold, or in italics
2. The letter ‘c’ followed by chapter number of the Act – in brackets
3. Place of publication – followed by a comma
4. Publisher – followed by a full stop.
So something like:
Mental Capacity Act 2005 (c 9) London, HMSO.