Disputes over implementation of the Northern Ireland protocol have become “the achilles heel” of the EU’s relations with the UK, the German foreign minister said on Thursday as she held talks with her UK counterpart in London. Annalena Baerbock’s appeal to find a solution to the deadlock over the protocol came during wide-ranging and much delayed talks with James Cleverly in London, which also covered the war in Ukraine and the state of Anglo-German relations. Baerbock, a former student at the London School of Economics, said she had felt Brexit like the loss of a family member but that she was determined not to look back in anger. In a reference to the protocol, which sets out post-Brexit checks and standards in Northern Ireland, she said: “It is key that we find a responsible and pragmatic solution for Northern Ireland on the basis of existing agreements. It is the only way we will realise the full potential of our partnership. “As we engage in our new relationship, we are under an obligation to get the very best results for those who are directly affected. While we cannot turn back the clock we can decide to step forward into a good common future.” She pointedly urged the UK not to act in breach of international law, warning that it would be harder to make the case for order based on international rules at the UN security council. Baerbock’s remarks show there is a willingness in Europe to test whether or not the government of Rishi Sunak is willing to look for a solution to the dispute that has blighted relations with the EU, and to a lesser extent the US, since Brexit. But the achilles heel reference also underlines how the post-Brexit trade deal’s impact in Northern Ireland is holding back progress on other issues, including the Horizon scientific funding programme and wider political cooperation. Germany is eager to improve bilateral relations with the UK as it sees daily contact with the UK in rapid decline, symbolised by the drop in German language teaching in British schools. In their talks at Lancaster House, the two sides agreed to revive a long defunct cultural commission and to bring the 500 German and British twinned towns and cities into the digital age. Cleverly said Britain’s problems with the protocol were longstanding, but he welcomed “the much more constructive tone” between the UK and the commission. “It is a precursor to success, even if it is alone not enough.” Baerbock would not be involved in detailed future talks on the protocol, which would be conducted by the European Commission, but Germany could certainly set the tone. Relations between Baerbock, a strong supporter of arming Ukraine, and the UK government, are broadly good, even though the German Greens’ ethical foreign policy might seem a long way from that of the UK Conservative party. Before the visit Baerbock said she wanted to discuss with the British further sanctions against Russia, weapons transfers to Ukraine and winter relief – all designed to make Vladimir Putin recognise that “his brutal war of aggression is doomed to fail”.