Is the UK at war with Iran or not?

Keir Starmer has agreed to a US request to use British military bases for "defensive" strikes on Iranian missile sites. But the Prime Minister said the UK has learned lessons from the "mistakes of Iraq", and was not involved in the strikes on Iran. So why are we letting the US bomb Iran from our bases if we can’t say whether we support the war or not? The News Agents is brought to you by HSBC UK - https://www.hsbc.co.uk/