NATO Secretary General Anders Fogh Rasmussen has spoken of an alarming build-up of Russian ground and air forces close to the border with Ukraine.
He condemned Russia for sending a "so-called humanitarian convoy" into Ukraine without the consent of the Ukrainian authorities.
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Shadow chancellor John McDonnell has backed a free vote for MPs on the issue.
Savers into the new scheme can expect rates as high as 4 per cent from some banks.