UK politics: UK will have had five prime ministers in six yearsPublished20 October 2022Image caption, As Liz Truss resigned from her job as prime minister, she announced that a new leadership contest would take place over the coming week. Whoever wins will become the fifth PM in six years and the third in 2022 alone. Let's look back at the last four.Image source, Getty ImagesImage caption, Liz Truss became PM in September 2022 following the leadership election to replace Boris Johnson. However her grand plan fell apart as world financial markets and many of her own MPs reacted badly to her plans for the UK, during the cost of living crisis. She had to sack her allies and scrap her plans but it wasn't enough and she lost the support of too many of the Conservative Party to continue.Image source, Getty ImagesImage caption, Boris Johnson ran the campaign behind Brexit and, when he took charge, called and won a huge election promising to "get it done". He was in charge during the pandemic and the start of the war in Ukraine. However a series of scandals, including being fined by police over parties in lockdown, led to many of his own top team resigning and forcing him to stand down.Image source, Getty ImagesImage caption, Theresa May was the person left standing after the Conservative contest to replace David Cameron. Her task was to agree a Brexit deal with European leaders but she faced lots of opposition from her own party and from others. In the end she wasn't able to keep enough people on her side and she stood down, launching a contest won by Mr Johnson.Image source, Getty ImagesImage caption, Do you remember this PM? His name is David Cameron and he was in charge from 2010 to 2016. It was he who called the referendum on the UK leaving the European Union to try to stop arguments in the Conservative Party. He supported staying in the EU and when the vote went the other way, he resigned as prime minster.