David Cameron
It may be down an illegitimate line, but David Cameron has royal blood in him, being a descendent of King William IV, who reigned in the early part of the 19th Century. William fathered no fewer than ten illegitimate children with the same woman, his mistress Dorethea Jordan. One of them was the PM's great-great-great-great-grandmother, which means that Cameron is a fifth cousin of the Queen.
Although illegitimate lines aren't in themselves 'posh', many of Cameron's ancestors on his father's side included the Countess of Erroll, who achieved the title through marriage. And if you think Cameron's surname sounds Scottish, that's because it is. His ancestors around the turn of the 20th Century built and owned Blairmore House, a country pile in Aberdeenshire. That was sold in the 1930s and turned into a private school.
Cameron also counts baronets in his family tree on his maternal side - his grandfather was Sir William Mount, 2nd Baronet of Wasing. Unfortunately Sir William only had daughters so the baronetcy was transfered to his nephew when he died. One of Williams' daughters married Ian Cameron, who was a wealthy stockbroker.
Ed Miliband
Ed Miliband often talks about his Polish-Jewish heritage in speeches, saying how proud he is that Britain took in his parents Ralph and Marion when they fled the Holocaust.
Miliband's father Ralph died in 1994, and was one of the leading Marxist writers of the 20th Century, producing seven major works of political theory and publishing well into the early 1990s. Ralph Miliband resided in Belgium before fleeing the advancing Nazis.
Ed's grandfather, Sam, was a member of the Russian Red Army, before emigrating to Poland to become a leatherworker.
Ed's mother, Marion Kozak, is guarded about her dramatic life. But The Telegraph recently profiled her story, cataloguing how she was born Dobra Jenta Kozak and grew up in southwest Poland, the daughter of a wealthy Jewish family. When the Germans invaded her home town of Czestochowa in 1942, it began a train of events which saw her in constant danger, fleeing the and hiding from SS guards until the end of the war.
In 1947 a Jewish organisation arranged for her to be sent to Britain, an orphan, not knowing any English. Despite this she learned quickly and met Ralph while studying at the London School of Economics in the 1960s.
Nick Clegg
Nick Clegg is actually only one-quarter English, with much of his lineage being Dutch and Russian. In fact his mother, Kira Engelhardt, is a Baroness with links to the Russian aristocracy. Clegg's great-great-grandfather on his paternal side was Ignaty Zakrevsky, Attorney General of the Imperial Russian senate.
Clegg would be a great candidate for "Who do you think you are?", because there's a lot about his genealogy which remains shrouded in mystery. Baroness Moura Budberg, Clegg's great-great-aunt, was a Russian writer popularly believed to be a spy, possibly as a British double agent.
Clegg's great-grandfather on his paternal side comes from tamer clergy stock, but his maternal lineage is peppered with anguish, with his Dutch mother being interned in a concentration camp in Jakarta by the Japanese army during the Second World War. She moved to England in the late 1950s where she met Clegg's father, also called Nick.
Alex Salmond
Of our four main political leaders, Alex Salmond comes from the most humble of stock. Although the Scottish First Minister is fiercely private and won't speak about his family life at all during interviews, census records show his lineage can be traced back to the Seventeenth Century, when his forebears worked the land as agricultural labourers in Stirlingshire.
Census records suggest that his family was part of a "large-scale depopulation" of rural areas of Scotland in the mid 19th Century, possibly linked to the notorious Highland Clearances which saw landowners booting tens of thousands of workers off their land.
From the 1870s onwards Salmond's ancestors moved to Linlithgow in West Lothian. His parents were civil servants and Salmond came from moderately modest beginnings, attending Linlithgow Academy, a state school.
Of all our political leaders, Salmond arguably has the greatest prospect of making a huge mark on the history of Britain by securing Scottish independence. Interesting then, that compared with Cameron, Clegg and Miliband, his ancestry is perhaps the least turbulent!