Why tell the world the UK is giving missile blueprints to Ukraine?

Why on earth has Andy Burnham, newish UK prime minister, announced to the world that he has approved giving missile blueprints to Ukraine so that Kyiv can make its own version of the weapon? Sure, it's good to remind Vladimir Putin that the West is on Ukraine's side. But something which should have been kept secret has been blurted out like it's intended as a slap in the face for the Kremlin. Good on yer, some might say. But the most important responsibility for Burnham is to keep this country safe, not Ukraine's, and telling Putin that the UK is handing classified blueprints to Kyiv seems to me to be foolish at the very least. Putin is already targeting Britain with cyber warfare, close-in submarines and warships. Why invite mnore aggression from Moscow? The blueprints are for components of the UK's Storm Shadow cruise missile which was jointly developed with the French who call it Scalp Mrk 2. It's a pretty fancy piece of kit which has been used by Ukraine since 2023 anbd is now regularly fired at targets inside Russia. The plan is for Kyiv to have its own factory churning out Storm Shadow/Scalps. But why the huge publicity? The first thing Russia will do is start hitting the factory. There are occasions when secrecy is justified. This is one of them.