This bill allows for a referendum on the electoral system if 5% of the electorate sign a petition.
See if your MP has signed EDM 1028 here, and if not send them a letter.
I notice that only 62 MPs have signed it so far - 18 Labour, 39 Lib Dem and 5 others (no Tories - what a surprise). It seems strange that there are 24 Lib Dem MPs who have yet to sign and quite a few of the smaller parties haven't signed either. I wonder why?