Can Labour people be friends with Tories?
It is the love that dare not speak its name - so how many Labour Party members are secretly friends with Conservatives?
You don't have to look far at Labour's annual conference in Brighton to see badges and T-shirts with the slogan "never kissed a Tory".
It might be a bit of fun, but some people have read a deeper meaning into the slogan, seeing it as a depressing sign of our politically divided, tribal times.
Surely people can put aside their political differences in the name of friendship or even romance?
The slogan "is meant to be very tongue-in-cheek, not divisive or hostile", says Mancunian Chris Wills, who sells badges at the LGBT stand. In any case, the Conservatives have their own versions of it, he says, likely referring to "I kissed a Tory (and I liked it)".
The idea of fraternising with the enemy is anathema to many old school socialists.
"I don't want to spend my time going on holidays with a Tory," veteran Labour MP Dennis Skinner tells the BBC.
"The idea would be appalling. When you go on holiday you want to enjoy yourself, not be arguing the toss about different things."
Does he have friends who are Tories? "Doubt it. But it doesn't matter to me at all, I've never even given it a thought until you've raised it. I think it's a crazy notion."
Others take a more relaxed view of making friends across Westminster's political divide.
Ealing North MP Stephen Pound - who once joked that he would disown his daughter if she came home with a Tory - suggested Labour MPs have always chummed up with those sitting on the Conservative benches on the other side of the House of Commons chamber.
"The tradition is that your opponents are sitting opposite you but your enemies are behind you," he says.
"Nigel Evans (Tory MP for Ribble Valley) and I have an understanding and we have been close friends for many years.
"I am friendly with Tories because I wish to show them the error of their ways, and show them the paths of righteousness."
This might reflect the reality of life at Westminster, where MPs from all sides work together on committees and swap cross-party gossip in the bars and restaurants, away from the tribal name-calling that we see on TV.
But some MPs arrive at the place determined not to be seduced into friendly relations with the other side.
Recently-elected Labour MP Laura Pidcock caused a stir last month when she said she had "absolutely no intention" of being friends with any of the Conservatives she encountered at Westminster.
Stephen Stanners, from Blyth Valley, says Ms Pidcock's comments had been "slightly twisted" (she later clarified that she represented all her constituents and would work with Tories in their interests).
"At the end of the day she's not in Parliament to make friends, she's there to do a job for her constituents," he said.
Vince Barry, chairman of Plymouth Labour Students, said he had personal friends who vote Conservative.
"It's difficult if you start talking about politics but as long as you stay away from politics it's OK," he advised.
As a Labour councillor Jo Sergeant, from Bristol, is happy with to work with her political opponents.
"On a personal level they're OK," she says.
Her fellow councillor Harriet Bradley adds: "Not friends, but I have got a lot of Tories in my extended family. They tease me and I just keep quiet about it."
But Chris Owen from Dewsbury doesn't keep quiet.
"If there are friends of mine who are Tories I persuade them it's the wrong thing to do," he says.
"I am a committed socialist, and that comes through with people."
His friend, Paul Cooney from Huddersfield, advises "setting parameters" to avoid discussing controversial topics.