Barring any massive shift in public opinion, Ukip will gain its first elected MP in just a few weeks time on 9 October. Parliamentary by-elections may normally be of interest only to political anoraks, but this one could have a profound and lasting impact on the UK.
Douglas Carswell did the honourable thing by 'resigning' his seat and forcing a by-election (MPs can't legally resign of course, so the arcane method of forcing a by-election is for him to become the Steward of the Manor of Northstead which disqualifies him temporarily from being an MP). He was elected as a Conservative, so when he changed parties to Ukip it's commendable and utterly democratic that he chose to ask the electorate whether they still want him as a Ukip MP.
Ukip members are still in shock from the two opinion polls conducted in Clacton. They show Ukip on an astronomical 56% and 64% of the vote (the 56% poll being conducted by the Conservative Lord Ashcroft). Carswell is certainly opposed to British membership of the European Union, but I think his decision to join Ukip is about more than that.
The Coalition Agreement in 2010 included many reforms to make the system more democratic, including giving voters the right to 'recall' corrupt MPs and vote them out of office immediately. Douglas Carswell is a huge supporter of this, and of increased democracy in general. Almost all of the Coalition measures have not happened. Lip-service has been paid to democracy but when it came down to it, other things were considered more important.
By the terms of that agreement, Ukip should have had 20+ new members of the House of Lords and even the Green Party should have had a dozen or so. The Greens have had 1; Ukip 0.
If Carswell is reelected next month, we can definitively say that we have a four-party system in the UK. At every level other than General Elections, Ukip has been in third place or better:
1. Ukip took far more votes than the Liberal Democrats at the 2012 and 2013 Council elections.
2. Ukip has finished second at a string of Parliamentary by-elections; the Lib Dems have lost many deposits and in one case dropped to eighth place.
3. Opinion polls vary according to methodology, but 24 of the last 25 polls conducted by all companies put Ukip ahead of the Liberal Democrats.
4. Ukip won May's European elections, taking 24 MEPs. This is the first time in a century that a Party other than Labour or Conservatives have won a national election, and the Liberal Democrats finished in 5th place with just one seat.
One argument remains against Ukip being considered a major Party: Ukip has never actually won a Westminster seat. Indeed, a friend of mine who's a Conservative supporter was pointing this out to me very strongly just 48 hours before Carswell came across to Ukip.
If Ukip wins a Westminster seat next month, on what basis can Nigel Farage really be excluded from any televised leaders' debates at the General Election? Is it possible that OfCom could refuse to classify Ukip as a major party in 2015 - again, on what basis could it do so?
Ukip should go on to win seats in May - Thanet South, Thurrock and Clacton should return Ukip MPs, with many more Ukip targets. The by-election in Clacton isn't just a by-election. It's a question - do people want to stick to the old three-party system or is there room for a new player at Westminster?