Why, the American political humorist P.

J. O'Rourke once wondered, don't the Brits just let by-elections go by?

In some countries they do - Germany, for example - but in the UK these semi-regular micro elections ensure that political apparatchiks and scribes don't get bored.

By-elections, in other words, help gauge the political temperature, although they're generally pretty hopeless as predictors: think of all those SDP wins in the early 1980s, or indeed Govan and the SNP in 1988.

Which brings me to this Thursday's Clacton by-election. This, despite the Prime Minister's best efforts last week, is likely to give the Farage insurgency its first Member of Parliament.

From such small, dramatic beginnings, of course, can flow popular movements: think of Winnie Ewing seizing Hamilton from Labour in 1967; by the 1970 general election the SNP threat had apparently fizzled out, only to return four years later.

Listen to many independistas during the recent referendum campaign, however, and Ukip sweeping into government in coalition with the Conservatives was presented as a realistic prospect. Yet even if the party perform well next May their chances of picking up many MPs are slim.

Unless of course they know how to play the first-past-the-post system, a long-standing specialty of the Liberal Democrats, currently gathered in Glasgow for their annual conference. Indeed, speak to any Ukip strategist - and they're becoming increasingly professional - and they'll approvingly quote from the Lib Dem playbook.

Acutely aware of this, the Conservatives have been attempting to out-Ukip Ukip for some time now, stepping up their efforts with the rallying cry 'English Votes for English Laws'. Conscious that Ukip's appeal does not derive purely from unhappiness over Europe and (related) unhappiness over immigration, the once natural party of government is aiming squarely for the 'English' vote.

Last week friends of mine posted an image of the actor Giles Watling, the Conservative candidate in Clacton, with the St George's Cross and the EVEL pledge. At least one expressed disapproval, but, as I pointed out in response, if it had been a Scottish Nationalist candidate next to a Saltire and the slogan 'Scottish Control of Scottish Affairs' (incidentally an old Unionist phrase), no one would have batted an eyelid.

On a similar note, I can't help feeling that Tory rhetoric around the European Convention on Human Rights is curiously familiar - i.e. when it comes to human rights there ought to be British Control of British Affairs. In the Prime Minister's words, the ECHR is one of two things that need 'sorting out', the other being the EU.

"So we're going to go in as a country," Cam told his troops last Wednesday, "get our powers back, fight for our national interest and yes - we'll put it to a referendum, in or out - it will be your choice." Again the pitch, even down to the proposed plebiscite, is constitutionally familiar, although it's the "indy-lite" version of Ukip's real deal.

For Ukip continue to sell the beguilingly simple idea of "independence" - British independence from the European Union. Naturally this takes different forms: in Tory constituencies Ukip pose as a more authentic version of the Conservative Party, and in Labour strongholds as defenders of the disenfranchised working class.

They are, in other words, all things to all men, railing against the "Westminster elite" while skirting over a multitude of intellectual contortions. But if one considers, as many do, Ukip's raison d'etre to be swivel-eyed stuff, why then is its Scottish corollary taken comparatively seriously? Both preach unqualified independence in a world where no such thing exists.

Had there been a Yes vote a few weeks ago then Scotland, contrary to the rhetoric, would ultimately have ended up with non-Scots in London and Brussels continuing to make decisions about Scotland, while under Ukip's preferred outcome the UK would eventually resemble Norway and Switzerland - superficially detached from the EU but in reality subject to its laws, regulations and endless bilateral agreements.

Both outcomes would lead to massive democratic deficits having effectively disenfranchised their respective states from broader pan-UK or pan-EU governance. In a Scottish contest this is all the more ironic given that the SNP's stance is actually a moderately Eurosceptic one: anti-Euro, anti-CFP and anti-closer fiscal integration. A few years ago the Scottish Government even railed against interference from UK Supreme Court judges using rhetoric that anticipated the current Tory onslaught against the ECHR.

Last Wednesday I watched the UK's EU commissioner-elect, Lord Hill, square similar circles during his "hearing" in the European Parliament. "I want Britain to be part of a successful European Union," he told MEPs, while also pledging to put "the common European interest" before the City of London. To earn extra brownie points he even delivered his opening salvo in French, "the language of Moliere".

Lord Hill's Hugh Grant routine, however, didn't quite have the desired effect, but then if I were a Europhile MEP I too would be sceptical of mixed messages: as the would-be commissioner protested a little too much, the man who nominated him was on his feet in Birmingham being markedly less constructive. Hill, as a consequence, faces another round of questioning this week: presumably his weekend disappeared amid voluminous briefing papers on the future of Eurobonds.

If confirmed, one of Lord Hill's responsibilities will be banking union and greater fiscal integration, a reminder that the "ever closer union" envisaged by Maastricht is very much a reality. Presumably he'll still be in post when the UK Government attempts to renegotiate freedom of movement. This, according to Cam, is a red-line issue, but it's also a complete non-starter. Being "in Europe but not run by Europe" - a bit like "independence in Europe" - might be fine as a slogan, but it's markedly less credible as realistic policy.

Nevertheless, John Edward, the former head of the European Parliament office in Scotland, is surely correct in his view that "a referendum of some kind … is probably inevitable", even if Cameron doesn't secure a second term next May. Edward also said he'd reached the reluctant conclusion that Scots were not necessarily "more pro-EU than the rest of the UK", merely "less anti".

But just as the pro-independence campaign asked some legitimate questions of the UK and how it's governed, so too do Ukip of the EU. If nothing else, referendums can provoke a reinvigorating national conversation, although, if the UK does face an in/out ballot by the end of 2017, the SNP will find itself in the uncomfortable position of appearing to deny Scots a voice in that conversation. Arguing that it might produce the wrong result isn't really an adequate critique.