IT TAKES a particular talent to transform a political disaster for the Tories to confirmation of why Labour has alienated millions of working-class voters.

Emily Thornberry’s sneery tweet of a house decorated with St George’s flags on its facade and a white van outside and captioned simply “Image from Rochester” encapsulates the contempt that the Labour metropolitan elite has for working people.

Ed Miliband is said to have gone ballistic when he saw the tweet, which will be remembered long after this by-election is forgotten.

Thornberry admirers suggest that she ought not to have resigned and that an apology would have sufficed.

Not at all. So devastating is this image for people of a similar background throughout England that Labour should replace her as general election candidate for Islington South and Finsbury.

While some of her constituency has been gentrified in recent decades, most of it remains solidly working class.

She would be ripped apart at the general election and the fallout would affect other parts of the country.

No politician would dream of making an issue of a house in Scotland or Wales groaning under the weight of St Andrew’s crosses or red dragons.

Yet the Westminster elite considers it acceptable to sneer at English people’s identification with their football team or pride in their nationality, even if Thornberry displayed her ignorance by calling the George’s crosses “British” flags.

Far better George’s flag than the Butcher’s Apron that was flown all over the world to signify colonial domination by the unlamented British empire.

Miliband is sufficiently astute to understand the enormity of this tweet, but he is partly responsible for the debacle by virtue of the low-key campaign Labour ran in Rochester and Strood.

If Labour’s polling “strategists” weren’t so smart-arsed as to believe that their party would benefit from Ukip embarrassment of the Tories in an erstwhile safe seat while Labour lurked smugly in the background, they would have seen that this contest was winnable.

Labour had a good candidate in Naushabah Khan who could, and did, take on the bigots.

Had she not been saddled with the “tougher immigration controls” and “benefit curbs for EC citizens” rhetoric of Yvette Cooper and Rachel Reeves, she could have waged an aggressive and possibly successful campaign on ground favourable to Labour rather than Ukip’s chosen field.

Voters trot out anti-migrant stuff in vox-pops because it’s drummed into their heads by the mass media.

But they go on to reveal their real concerns as employment, pay and conditions, housing, health and education.

In return, Labour frontbenchers jangle on inconsequentially, as Chris Leslie did yesterday, about balancing the books, which means continuing the Tory cuts agenda, but perhaps not so quickly.

Who is supposed to be enthused by such an uninspiring recitation of “responsible” blather?

Labour will, as ever, depend on its traditional base next May in bidding for office, but when did the party last mention the working class, never mind base its programme on meeting workers’ needs?

Ukip posh boys Nigel Farage and Mark Reckless now pose proudly as the “voice of the working class” because Labour has left the field open to them.

Labour will never win mass support by fighting Ukip and the Tories on who can treat immigrants most abominably.

Its best option is through a fighting class approach that tackles the issues that matter most to working people.