Complex sentence: After the UK 2010 general election, the new coalition government agreed to stage a referendum on voting reform, which took place on 5 May 2011, with voters given the choice of switching to the Alternative Vote system or retaining the current one.
Split into simpler sentences: After the UK 2010 general election, the new coalition government agreed to hold a referendum on voting reform. This took place on 5 May 2011: voters were given the choice of switching to the Alternative Vote system or retaining the current one.