A difference of political opinion between siblings can make for awkward encounters around the family dinner table.
Here, the Press Association looks at cases where sibling solidarity might have been tested by politics:
Annunziata and Jacob Rees-Mogg
The sister of the prominent Conservative backbencher and Brexiteer was unveiled as a surprise candidate for Nigel Farage’s new Brexit Party in the forthcoming European elections on Friday.
Annunziata said it had not been a decision she had taken lightly after more than three decades of supporting the Tories.
While they may now back different political parties, they at least share the same passion for leaving the EU.
Jeremy and Piers Corbyn
The Labour leader, a long-time Eurosceptic, was forced to defend his conduct during the EU referendum campaign amid criticisms that he offered no more than lukewarm support for Remain.
Shadow chancellor and long-time ally John McDonnell backed the veteran politician’s attitude during the campaign, adding: “He’s where the British public are, which is basically Eurosceptical to a certain extent but believes Remain is the best thing.”
Publicly, there was only one Corbyn brother cheering as the referendum result trickled through. And Piers was in good company – at the triumphant Leave.EU party in central London alongside the likes of a jubilant Nigel Farage.
Ed and David Miliband
Rumours of a rift between the brothers dominated the 2010 Labour leadership election.
And it was laid bare when a barbed remark by the then-shadow foreign secretary was caught on camera as Ed tried to kick-start his stewardship of the party following the vote which saw him triumph over his brother.
It was Ed’s blunt description of the decision to invade Iraq in 2003 as “wrong” that provoked an angry response from David, who turned to then-Labour deputy leader Harriet Harman and said: “You voted for it, why are you clapping?”
Ms Harman was seen to reply: “I’m clapping because he is the leader. I’m supporting him.”
David stood down from the Labour front bench within days, and quit as an MP in 2013.
Boris and Jo Johnson
Both are members of the Tory party, and both resigned as ministers over Brexit.
But while Boris – the de facto leader of the Leave campaign during the referendum – quit the Foreign Secretary role over Theresa May’s Chequers plan, Remain-supporting Jo handed in his transport brief when he warned that the UK was “on the brink of the greatest crisis since the Second World War”.
He said that an attempt to force Brexit through without a second referendum would “do grave damage to our democracy”.
The duo’s sister Rachel also made headlines for her tough stance on Brexit – removing her blouse while appearing on Sky News in support of Remaining in the EU.