The World Tonight

Iran has threatened shipping in the Persian Gulf and Straits of Hormuz as fighting between the country and the US and Israel escalates. Today, US President Donald Trump says he took the decision to launch a war against Iran because it was the "last, best chance" to stop the country's regime. We devote the entire programme to the conflict, and enlist a panel of experts to guide us through it: Rana Rahimpour is an Iranian-British journalist and former BBC Persian presenter and reporter; Kirsten Fontenrose was senior director for the Gulf at The US National Security Council in the first Trump Administration; and Sir Simon Fraser is a former head of the Foreign Office, now Chair of the British foreign policy institute Chatham House.
Here in the UK, Sir Keir Starmer has said the UK's decision not to join the US-Israeli strikes on Iran was "deliberate", adding his government "does not believe in regime change from the skies". We assess the state of relations between the US and UK.

Allegations of 'family voting' in the Gorton and Denton by-election are to be raised in parliament on Monday. We speak to Lord Pickles, whose report into electoral fraud called for action a decade ago. We also look at where the by-election leaves Labour strategy: are Reform or the Greens their main opposition now? Also:Bill Clinton testifies in front of a Congressional committee; President Trump says he's "not happy" as concerns grow about a possible US attack. And 30 years of Pokemon.

It’s expected to be a close race between Labour, Reform UK, and the Greens. We hear from the count and speak to political scientist Paula Keaveney about the apparent fragmentation of British politics.
Also on programme: Democrats on the Republican-led House Oversight Committee have defended the former US Secretary of State Hillary Clinton after her deposition about the late sex offender Jeffrey Epstein.
And the television series Our Friends in the North is adapted for the stage. Writer Peter Flannery and actor Christopher Eccleston discuss the show’s enduring success.

The government has said it is not pausing legislation that would see the Chagos Islands transferred to Mauritius. That's despite Foreign Office minister Hamish Falconer telling Parliament that the process would be paused "for discussions with our American counterparts". A government spokesperson said Falconer had "misspoken".
Also on the programme: as more shops use facial recognition technology to deter shoplifters, we find out what it’s like to be falsely accused.
And new research uncovers clues to the origin of the organ that gave Charles Darwin a "cold shudder": the eye.

Lord Mandelson was released in the early hours of Tuesday morning - and tonight lawyers for the former UK Ambassador and Labour minister have said he'd been arrested on "a baseless suggestion" that he was planning to leave the country.
Also on the programme: As the government prepares to introduce its criminal justice reforms, a justice minister insists they won't back down on plans to reduce the number of jury trials.
As the latest retail crime figures are released, the view from the frontline: our presenter visits Northampton to see how police are tackling shoplifting.
And there has been a dog among the swans tonight - but a friendly one: the co-owner of Swansea City Football Club - the American rapper Snoop Dogg - attends a home game for the first time.