Plaid Cymru’s byelection victory in the Welsh town of Caerphilly is unprecedented. Labour had won every election here for more than a century. Yet the result also feels strangely familiar.
Observers of British politics have become accustomed to waking up to unprecedented results. By the end of the previous Westminster parliament, record byelection swings against the incumbent government had become the norm, and elections at all levels had shown an electorate who were willing and able to identify the best-placed party to defeat a disliked option.
