The Ukrainian flag conundrum

If you walk down Whitehall, you will see numerous Ukrainian flags on government buildings. I approve the sentiments. Like many all over the country, we fly the Ukrainian flag in our garden. But is it right that the flag should be flown by HMG? On what basis, and by whom, is such a decision made? Just now, of course, the interests of the United Kingdom and of Ukraine are closely allied; but it is a basic principle of foreign policy that British interests may sometimes clash even with those of close allies. Suppose we fall out with Ukraine while the war continues. Would we keep the flags flying, thus looking hypocritical, or take them down, thus looking disloyal? If the state wishes to make a public gesture of support, surely it is better as a one-off, as when they played ‘The Star-Spangled Banner’ at the Queen’s request, when changing the guard just after 11 September 2001.