Some things in life, you put off and put off. The source of the procrastination may be tedium (all those red utility bills yellowing on the doormat), or fear about a medical problem such as tinnitus, which is probably no more than a whooshy noise in the ear, but might prove a symptom of a benign tumour (acoustic neuroma) if you took it to the doctor.
Which of those analogies best represents Ukip in the mind of the Prime Minister, I have no idea. Nigel Farage may strike David Cameron as something to be paid off to avoid being disconnected from Downing St at the next election, or as an ailment that needs investigating to establish whether it poses a real threat. If, on the other hand, he would rather continue ignoring Mr Farage and his gaggle of blazered patriots, one understands the temptation.
For me, ignoring Mr Farage during all the years in which he has buzzed away more as irritant than searing pain has been the only course, though not because he appears to be particularly unpleasant. Far from it, if you fancied buying an MG from a Mayfair showroom in 1959, he would be the ideal salesman. A cross between a less engaging Terry-Thomas and a less repulsive Peter Alliss, he strikes me as a fine fellow for a brief chat about birds, jazz and mashie niblicks at the 19th, though not necessarily someone you'd care to find in the next seat on a Boeing 777 to Melbourne.
Stuck with Mr Farage for the long haul, however, is what we seem to be. With Ukip up to 14 per cent in one poll, and apparently heading north, this comic figure must be taken seriously.
According to another amusing politician, the insanely bewigged Conservative vice-chairman Michael Fabricant, Ukip's dilution of the core vote will cost the Tories 25 to 40 seats unless an electoral deal is cut. Both Messrs Farage and Cameron dismiss that idea at least for now. If the Mexican stand-off persists, Mr Farage may propel comparatively Eurotolerant Labour to power. With a cocktail of self-deprecation, bonhomie, tenacity and better political smarts than mainstream thinking has credited him (he has been typically cute in taking advantage of blue-rinse antipathy to gay marriage), he has fashioned himself into a mainstream player. By dint of a rigid consistency born of principles which, whether one likes them or not, are obviously genuine, he has come to speak for a sizeable minority of Thatcherite Tories (and, to a lesser extent, traditional Labour voters).
All of this leaves the PM three options. He can offer a deal whereby Ukip withdraws parliamentary candidates from marginals in return for a post-election, straight in-or-out EU referendum in which Mr Cameron would have to fight for "in", knowing that his defeat and immediate resignation would be odds on. He can seek to nullify Ukip by moving the Tories so far to the right – on immigration, welfare and taxation as well as Europe – that he cedes every inch of the centre ground to Ed Miliband and virtually ensures a Labour victory. Or, hoping to God that it's idiopathic background noise and not a tumour, he can go on trying to live with that infuriating buzz as best he can. Which is the least hideous option is hard to call, but a hunch says he can forget the last. The time for ignoring Nigel Farage has passed.