The Russian threat to Ukraine may be the first major foreign policy crisis since Brexit in which the UK can play to its strengths, and show that Britain with its military muscle is not turning into the global irrelevance that many had predicted. That at least is the hope in parts of Whitehall. The two other big post-Brexit foreign policy moments – the withdrawal from Afghanistan, and the announcement of the Aukus security partnership in the Indo-Pacific – did not exactly see Britain in the cockpit in the same way. The UK departed from Afghanistan under US duress and then executed that withdrawal so chaotically that it cost Dominic Raab his foreign secretaryship. Aukus was largely a US-Australian deal, even if puts the UK in a potentially leading role in the Indo-Pacific in future. But the Ukraine crisis is a different test, and one that the UK’s extensive diplomatic network dare not fail if it is to prove that outside the EU bloc, the UK has acquired a new foreign policy agility. At a personal level, Boris Johnson also hopes Ukraine will be his deus ex machina, a moment to prove to his sceptical backbenchers that he can show statesmanship and, more cynically, to shame the media into ending its “trivial obsessions” with “partygate”. As a result many of the recent Downing Street briefings prepared for the Sunday papers have had a somewhat desperate quality to them, portraying Johnson as being at the centre of grave, fast-moving world events. This contrasts with the harsher reality of scheduled calls to Vladimir Putin being cancelled because Johnson was detained by MPs asking him if they were fools to have complied with the Covid rules that he had set. The Russian president was never likely to see Johnson as an important interlocutor in the same league as the French president, Emmanuel Macron. Putin can also detect weakness in his opponents, and as soon as he sees a man is down, his first instinct is to kick as hard as he can. The call has now been rescheduled, but it is an embarrassing episode. It was also a bad stroke of luck that Liz Truss, the foreign secretary, was struck by Covid just before she headed on a diplomatic tour of eastern Europe. But that is not the whole picture or a fair description of how active the UK has been throughout the crisis. Britain has a clear-eyed sense of the issues at stake – the defence of the security architecture stuck in the wake of the collapse of the Soviet Union, all set out in the widely praised article by the defence secretary, Ben Wallace, debunking Putin’s claims about Ukraine’s historic origins. The UK also has a deep, long-standing military connection with Ukraine – confirmed last year in a new strategic partnership upon which it is now building through the provision of next generation anti-tank weapons. Through Chatham House there has been a steady flow of exchanges with Ukraine’s leading figures, covering energy, civil society and banking, going back a decade. The UK now hopes that military alliance with Ukraine can be extended by drawing in another close British ally, Poland – an idea enthusiastically endorsed by the Polish prime minister, Mateusz Morawiecki. It may even prove to be a way of drawing Ukraine closer to an informal security alliance with Nato partners without actually joining Nato itself – something which is off the table for the foreseeable future anyway. It would represent a balance to the Weimar Triangle, the much older alliance between Germany, France and Poland. All that helps to make Johnson a priority in Kyiv as European premiers jostle to fly into Ukraine. But there is a bigger prize for the UK. If it plays its cards right, It can re-establish itself as the undisputed No 1 ally of the US. UK intelligence services are working in lockstep with Washington, for instance over claims of a Russian inspired coup. Some reports suggest the US handed the UK the intelligence evidence to allow Truss to unmask the alleged plotters. Equally, British and US assessment of the high likelihood of an invasion is largely pitched at the same level. Britain’s leading cyber-experts have been flying to Washington to discuss what counter-measures can be prepared. Johnson has not been averse to reminding Washington of the UK’s reliability by chastising his former EU rivals France and Germany. Doubtless echoing what his diplomats were hearing in Washington, Johnson has warned Macron not to seek to exploit the crisis to promote his project of European strategic autonomy. Germany, he and Truss now repeatedly say, is too dependent on Russian gas, an analysis shared on a bipartisan basis by many in the US Congress. For a variety of historic and geographical reasons Germany was always going to end up the outlier in this crisis, but none of this is helped by a new coalition government still bedding in. It has even led the UK Foreign Office to lobby Washington to ask for an expansion of the Normandy format, from which the UK and the US are currently excluded. As the key forum in which the status of eastern Ukraine is discussed with Russia, Britain deeply regrets its self-exclusion. Above all, UK diplomats, along with the Ministry of Defence are trying to make themselves useful by using its influence in its network of former allies inside the EU, including in the Baltic states and eastern Europe. The Baltic states need no persuading about the Russian threat, and are privately, and sometimes in public, frustrated with Germany’s refusal to let them give Ukraine weaponry of German origin. More UK troops will go to Estonia if Nato requests. But Wallace is also putting in the air miles touring the EU countries where the UK message on the Russian threat faces a tougher reception: Slovakia, Hungary and Croatia. On Monday, Wallace – currently top of a cabinet league table monthly members’ poll on the ConservativeHome website – made little progress in Budapest with the Hungarian defence secretary who, at a joint press conference, said he opposed sanctions on Russia or more Nato troops in his country. On Tuesday, Wallace popped up in Croatia. Johnson has also been on the phone to Recep Tayyip Erdoğan of Turkey, a Nato member and potential wild card. There is of course one problem with all this frenetic activity and with the policy towards Moscow: Britain’s lax approach to Russian oligarchs based in the UK. It is now out there as a drag anchor on everything the UK seeks to do internationally about Russia. The shadow foreign secretary, David Lammy, was correct on Monday when he said that report and after report has been published highlighting this problem, and yet the government has refused to act. None of the measures announced this week by the Foreign Office will be implemented unless an invasion occurs, so the basic problem remains untouched. With Joe Biden making the fight against corruption one of his big themes, it was inevitable that Washington was going to lose patience with the UK’s sloth.