The alternative vote referendum, as part of the Conservative — Liberal Democrat Coalition Agreement drawn up after the 2010 general election, was a nationwide vote held on Thursday 5 May 2011 (the same date as local elections in many areas) to choose the method of electing MPs at subsequent general elections. (en.wikipedia.org)
Here is a quick look at the relationship between the BBC Projected National Share of the vote (PNS) in the local elections and the outcome of subsequent general elections. (electionsetc.com)
At three subsequent General Elections Scotland has sent just one Scottish Tory to Westminster. (conservativehome.blogs.com)