Your best bet is to go to the parties' web-sites themselves.
http://www.conservatives.com/ The Conservative Party (alias Tories),
http://www.labour.org.uk/home The Labour Party,
http://www.libdems.org.uk/ The Liberal Democrats - the third party constantly claims to be on the verge of a 'break through' currently has around 60 seat in the Commons (out of 659),
http://www.ukip.org/ The United Kingdom Independence Party - minor party, unlikely to gain any seats in the Commons though they do have M.E.P.s opposed to our continued membership of the European Union, in many ways a bunch of nutters one sensible policy notwithstanding.
I am sure that I don't have to remind you to take all of the pages
cum grano salis as they contain the parties' own spin on matters.