Sir Keir Starmer argues he has made "hard-edged" decisions, one day after his defence secretary quit in a row over money.
Ex-Defence Secretary John Healey has said the defence investment plan is "well short of what is required".
The case is believed to be the first time that convictions for criminal damage have been classified as terrorism.
The ban forms part of the government's package of sanctions on Moscow due to the ongoing war with Ukraine.
The artist, who has died at the age of 88, "was one of life's true originals", King Charles says.