https://www.independent.co.uk/news/uk/crime/elephant-castle-tube-station-attack-robbery-london-british-transport-police-a8964936.html
/// "The victim, a man, reported he had been sprayed with a substance. He was treated at the scene by paramedics; the victim suffered a minor irritation to his face," a spokesperson said. ///
/// Officers remained at the scene, the spokesperson added, but said test had confirmed the substance was not acid. ///
That's good to hear, at least that lets a certain comedian off the hook.
It would seem that they are now quick to rule out other things, just as they are regarding terrorism.