Put basically, if the Bill on electoral reform passes in the Commons we may see a Referendum on the use of AV as a voting system in the country as opposed to "First Past the Post". Note that it's a Referendum that would take place if the Bill is passed, not AV itself becoming law. That would be a matter for the British public direct.
But the Tories are opposed to this! Why because they are scared. After a week of vindictive personal sniping and indulging in old petty prejudices it is clear they are scared, as some Opinion Polls suggest they are not doing well.
Thing is! As Jack Straw has said, what are they afraid of! The issue will go to a Referendum, then they can put their case to the British people. Are they that scared of the public?
Tonight is definetly a night to keep an eye on Westminster