to defend ukraine itself, but a small contingent of british troops is in the country, here helping train ukrainian forces to repel any attack. we've supplied anti—tank missiles, defensive weapons. we're giving support to the ukrainian navy, we're giving support to the ukrainian energy sector to help them become more energy independent, so we really are giving every possible support we can to ukraine and we are one of the leading donors of lethal aid to ukraine to make sure that they are in the best possible position to defend themselves. these are ukrainian troops on the border of russia, preparing for the worst. they will be the ones on the frontline if russia does invade. but alongside the deterrents and defence this week, expect a flurry of diplomatic activity, too, to try to prevent a war that no—one says they want. a war that would have consequences far beyond ukraine's borders. caroline hawley, bbc news.