Surfball was supposed to be the sport of the next generation – but it instead it was a fiction created by Peter Mandelson.

Lying in politics is nothing new, but after the budget, Rachel Reeves' extraordinary pitch-rolling was viewed by some as an outright lie and others as justifiable spin. Inspired by this grey area, host Sascha O'Sullivan tries to find out the difference.

BBC Radio 4 Presenter Nick Robinson tells Sascha how he can spot when a politician is lying and explains the difference between ministers making a justifiable argument and those who read "the line to take."

Former Keir Starmer Political Director Luke Sullivan says Rachel Reeves was "absolutely not" lying in the run-up to the budget and explains how Starmer made the most of Boris Johnson-era scandals when the Tory prime minister was accused of lying.

Craig Oliver, David Cameron's former director of communications, rehashes the fibs told during the Brexit referendum, telling Sascha there were attacks "that were straightforwardly untrue."

Sascha then digs in to what happens when a minister... fesses up. She speaks to Mark Harper, who resigned as immigration minister after discovering his cleaner did not have the right to work in the UK. Harper lost his job – but was welcomed back months later.

Full Fact Chief Executive Officer Chris Morris tells Sascha it's hard to distinguish outright lies and spin — because most of the time politicians quote half-truths wrapped up in narrative.

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