KYIV (Reuters) – Britain and Ukraine warned on Tuesday that any Russian incursion would be a massive mistake, pledging to work together to strengthen Ukraine’s defence capability. The two nations issued a joint statement issued following a meeting between British Prime Minister Boris Johnson and Ukrainian President Volodymyr Zelenskiy. “The leaders warned that any further Russian incursion in Ukraine would be a massive strategic mistake and have a stark humanitarian cost,” the statement said. (Reporting by Guy Faulconbridge and William James in London; Editing by Alistair Smout)