1. National Front
Gape open-mouthed, as though someone has just told you England has won the World Cup, and it had nothing whatsoever to do with a malign conspiracy by naughty refs. Run away as fast as you can to evade the stench of their Millwall armpits.
Gasp as follows:
WTF? Is that even a thing these days?
2. SWP/Spartacists/Any other miniscule gang of jackbooted Trotskyite thugs
As above. In any case, they aren't actually a party, just a men's club for bigoted, stereotypically white middle-class straight men.
Bit like the National Front, if you think about it!
Gape open-mouthed, as before, except struggle for a minute or two to catch your breath. No need to run away, these people are not quite in the same league as the previous two; but fidget a bit in your seat for a minute or two.
Oh, erm, by the way, lovely weather today, isn't it?
No, no, no, really... I mean, lovely weather. It is Britain after... um... never mind.
Oh by the way, you see that lad in the corner there who used to sleep at my house? He would just LOVE to hear your views on Keynesian economics or the finer points of vulgar-Rothbardite social critique.
4. Green Party
Piss yourself laughing. Then groan in inarticulate horror, as you realise that they might just not be joking, and that you might just have met one of... them.
5. Liberal Democrats
Stare blankly for a good ten minutes or so. Finally summon up the strength to murmur...
Frown, tug on your clothes in fury, and then offer to be their token pleb friend from 'an exotic clime.' This is a strategy that works very well not only for non-UK citizens, but anyone who is just vaguely 'north of the M1.'
Very well remunerable for a start.
Well, at least that's what the Tories think; and that's all that matters to them!
Assume a look of great interest, even if you feel crushingly apathetic. Ask them:
Corbyn or Blair?
If they look infuriated and resentful at your question, tell them:
Sorry, I didn't actually think you were one of them. Easy mistake to make.
If they are not angry at all, but immediately burst into tears and start wringing their hands in despair also say:
Sorry, I didn't think you were one of them. Easy mistake to make.
8. Final point:
If they belong to any of the parties above, or indeed any other political party in the UK be on your guard. (At least if they hold any significant role of responsibility in the party. In some cases, this will mean being an MP or even a cabinet minister. In other cases, it will mean handing out cry-biscuits once every three-quarter-decade or so).
Don't be lending them your house keys, credit cards, or access to the back of your fridge.
I'm guessing, by now, you can understand which of those three goes with which!