British Prime Minister David Cameron has been making bold, statesman-like noises about Islamic State and President Putin this week. Well, of course he has. It’s what desperate leaders always do when their domestic policies and popularity ratings are tanking.

Unfortunately, it may be too little too late.

Cameron has reached that stage in his political career where, even were he singlehandedly to liberate Mosul, personally undo the handcuffs of all the captive Yazidis, Christians and Shias, stop the Syrian civil war, and engineer an enduring peaceful settlement in the Ukraine, he would still go down in history as one of Britain’s lesser prime ministerial also-rans.

Indeed, it is looking increasingly as though his single most significant legacy will be the one summed up by the cover of this week’s Private Eye satirical magazine: David Cameron, perhaps even more so than charismatic leader Nigel Farage, is the man most responsible for rise and rise of the Britain’s tea party UKIP.

Consider the latest opinion polls.

YouGov/Sun poll CON 32%, LAB 35%, LDEM 8%, UKIP 15%

This spells out the situation in black and white. Cameron’s Conservatives stand barely a prayer of winning a working majority at the next UK general election. And this despite the fact that Cameron’s prime opponent, Labour leader Ed Miliband, is widely considered such a weird, comical, economically illiterate joke figure as to be almost unelectable. And also, despite the fact that Britain currently has one of the world’s most successful economies and is enjoying a house price boom which is making many of the people who ought naturally be drawn to voting Conservative earn more in a year, tax free, than they do from their day jobs.

Why then are the Conservatives still polling so relatively dismally?

Simple. Because a significant chunk of their natural voter base does not consider them worthy of the name “conservative.”

And most of the blame for this can be laid directly at Cameron’s door.

Cameron rose to power on a modernising ticket. The Conservatives – as his Home Secretary Theresa May once unhelpfully put it – were seen as “the nasty party.” So Cameron made it his mission to “detoxify the brand.”

Under the slogan “Vote Blue, Go Green”, he committed the party to hard-left environmental policies (heavily subsidised renewables; a war on “carbon”; the devastation of Britain’s matchlessly beautiful countryside with bat-chomping, bird-slicing eco-crucifixes) straight out of the manual of Luddite, anti-capitalist pressure groups like Greenpeace and Friends of the Earth.

He alienated social conservatives with his promotion of gay marriage.

He infuriated the Tory shires by bilking on his commitment to repeal the ban on fox hunting; by wiping out country-dwellers’ views and property values with wind turbines and solar farms; by sacking the one minister in his cabinet – Department of Environment, Food and Rural Affairs (DEFRA) Secretary Owen Paterson – who understood the needs of Britain’s rural communities.

He irked economic conservatives by failing – despite frequent protestations to the contrary – sufficiently to cut public spending and to address Britain’s growing debt burden.

He maddened traditionalists – not to mention one of the Conservative party’s most natural support bases: the military – with his swingeing defence cuts.

And if there were any remaining Conservatives not yet driven to apoplexy by his blithering centrism, he soon put paid to their loyalties with his stance on Europe. So much of what is wrong with Britain right now can be traced directly to its iniquitous and subordinate relationship with the European Union: the economically-damaging carbon dioxide emissions targets; the meddling directives assaulting personal freedom (on everything from pesticides to the kind of hair-dryer you are allowed to use); the out-of-control immigration….

Yet Cameron has made it abundantly clear where his sympathies lie. Yes, for cynical vote-grubbing purposes he has promised Britain a referendum on the EU in 2017. But Cameron himself believes – against all evidence – that it is in Britain’s interests to remain “shackled to the corpse” (Copyright Dan Hannan) of the EU for all eternity.

This isn’t the full list of Cameron’s crimes against conservatism, by the way. We haven’t mentioned his failure to reform the creaking, embarrassing and hideously expensive National Health Service; nor the rise and rise of fundamentalist Islam; nor his multiple surrenders to the political correctness lobby; nor the way he has allowed the Civil Service to be hijacked by the sinister communitarian commissar Jeremy Heywood; nor his inability to rein in all the meddling, costly, pointless Quangos run by doctrinaire leftist refugees from the Tony Blair and Gordon Brown administrations; nor his failure to conjure a sufficiently positive vision of British virtues to persuade Scotland of the overwhelming case for the survival of the Union.

Nor have we yet mentioned the reverse Midas touch by which Cameron managed to turn what ought to have been his administration’s greatest achievement almost to dust. Under his brilliant, inspired former Education Secretary Michael Gove, Britain’s schools underwent a radical transformation for the better that had proved beyond even the abilities of Margaret Thatcher.

Gove attacked the progressive educational establishment – the Blob – head on, gave schools more autonomy, restored rigour to exams, improved discipline, rewarded good teachers and sacked bad ones, and in the process, created a more socially just education system which rewarded excellence and which didn’t depend purely on your ability to afford private school fees or buy an expensive home in a decent state school catchment area.

Gove’s reward for this courage and hard work? To be sacked from his position and given the ignominious (and inappropriate, for a man of Gove’s particular talents) role of Chief Whip.

The assumption behind this betrayal of conservative values was that right-wing voters would grit their teeth and vote Conservative anyway because they had nowhere else to go. But unfortunately for Cameron and the Conservatives they do: the outfit sometimes known as the “Tory party in exile” – UKIP.

Is there any consolation the right can draw from this? In the short term, probably not. Unless Cameron manages to pull a miracle out of the hat – and it wouldn’t be the first time: he can be quite an impressive skin-saver when push comes to shove – then it seems most likely that by this time next year, Britain’s economy will be stagnating and her freedoms will be being curtailed by one of those most nakedly socialistic Labour governments in recent memory.

That’s at least four years, from 2015 onwards, when Britain will be an effective write-off.

After this Götterdämmerung, there may yet be cause for hope. The model is what happened in Canada to the Progressive Conservative Party – an outfit of Cameron-esque squishes driven, more or less to oblivion, by a more muscular right-wing party, resulting in the strong, reunited Conservative administration we see running Canada today.

The other model, of course, is what happened to the British Conservative party in the late 1970s. In this scenario, Cameron is the successor to the famously useless Conservative leader Edward Heath, without whose disastrous reign as Prime Minister the revolutionary change offered by his replacement, Margaret Thatcher, might never have seemed so urgent or desirable.

Sometimes in order to save the city you first have to destroy it. This, in effect, is what Cameron has done to British Conservatism: killing it but simultaneously reviving it. Without David Cameron, UKIP would never have grown so far or so fast, nor would the mostly conservative principles for which it stands have been made to look so refreshing and attractive.

UKIP leader Nigel Farage is in the US today, courting support and donations from his Tea Party confrères across the pond. I hope he finds space to drink a toast to the man he cordially loathes but to whom, au fond, he owes his career: David Cameron.