Now seems as good a time as any to remember this quote from Orwell.
"England is perhaps the only great country whose intellectuals are ashamed of their own nationality. In left-wing circles it is always felt that there is something slightly disgraceful in being an Englishman and that it is a duty to snigger at every English institution."
It still very much holds true today. The white van man controversy showed Labour's contempt for the working-class, as did Gordon Brown's dismissal of a working-class British woman's concerns over immigration as "bigoted". Diane Abbott;s promotion of seemingly every culture over the British one is indicative of this too.
Then we have the Greens, who so hate the UK that they think that it's acceptable to be part of a terrorist organisation, that terrorism is entirely the Western world's fault and that it is better to spend GDP propping up foreign dictators and funding India's space programme then it is spending money on protecting our country.
The SNP and Plaid Cymru are both anti-union, which I concede is more due to their nationalism than it is the fact that they are left-wing, but the fact remains that there does not appear to be a single major left-wing party which is not anti-British in some way.