More than 100 Ukrainians were killed in the 2013-14 EuroMaidan Revolution, partly a drive to to bring the nation closer to the EU’s founding values of democracy, rule of law and free trade.

That a country would willingly exit such a union is perplexing for many in Ukraine, which hopes to get the chance someday to join this club.

Ukrainians are not disinterested observers in the UK referendum – a Brexit vote would have implications for future security. Britain has been a stanch supporter of Ukraine, providing military aid in the form of training and equipment. More significantly, it has been conducting quiet diplomacy within the EU to keep member states from wavering on sanctions against Russia for its war against Ukraine. Many leave campaigners are more sympathetic to Moscow than Kyiv.

And should Britain leave the EU, it will enter a tortuous period of negotiations over trade with its former partners, which will absorb much of the attention of EU diplomacy for years. As UK journalist Ben Judah pointed out in a recent opinion piece in the Moscow Times, EU states that want to get back to business as usual with Russia will probably use this diplomatic horse-trading to extract concessions from Brussels and Berlin. The weakening of the EU’s position on Russia would only be a matter of time.

Moreover, a Brexit could even lead to the breakup of the UK, if a pro-EU Scotland pushed for another independence referendum, and a threat to the unity of the rest of the EU, as right-wing Euroskeptic parties on the continent, egged on no doubt by the Kremlin, pushed for their own in/out referendums. All that would greatly please Vladimir Putin’s Russia.

So if the leave camp in the UK does win the day, as they celebrate, they should take a moment to wonder why Britain’s enemies are celebrating along with them, and why the country’s friends and allies, many Ukrainians among them, are grieving their loss.