Russia has threatened to target British factories in a 'semi-military' response to the UK's support for Ukraine , as Vladimir Putin warned that a 'Pandora's box has been opened'.

The Prime Minister's trip is designed to signal the UK's continued support for the country's battle against Russia.

"Ukraine's security is our security," UK Prime Minister Andy Burnham said in a statement, adding that Britain would stand by Ukraine "for as long as it takes."