The British defence secretary, Ben Wallace, will join counterparts from Poland and the Baltic countries in Estonia to mount a final attempt to put pressure on Germany to authorise sending Leopard 2 tanks to Ukraine this week. The meeting of so-called “Leopard coalition” of countries willing to or keen to see western tanks sent to Kyiv comes a day before a group of about 50 defence ministers assemble in Ramstein, Germany to discuss future weapons shipments to Ukraine. Defence sources said a purpose of the meeting on Thursday was “to encourage the Germans” if no decision has been made by Berlin before then, although the German chancellor, Olaf Scholz, is due to speak at the Davos summit on Wednesday afternoon. Andrzej Duda, the Polish president, speaking at the Davos World Economic Forum on Tuesday, said a positive decision from Berlin to allow the re-export of German-manufactured Leopard 2 tanks was “very, very, very, very needed”, and that a group of Nato countries wanted to come together to help form an armoured brigade that could be given to Ukraine. He added: “I was asked by Volodymyr Zelenskiy for that military support a few times. He said to me: ‘Andrzej, we need those modern tanks because it is the only way to stop the Russian invasion.’” Earlier this week, Britain said it would donate a squadron of 14 of its Challenger 2 tanks to Kyiv, but that number is well below the 100 minimum that experts have said would be needed to allow Ukraine’s forces to achieve a breakthrough against Russia. However, there are more than 2,300 Leopard 2 tanks available or in storage across Europe in 13 countries, including Germany, and if a group of countries were to donate some of their tanks it could add up to a significant force on the battlefield. Berlin’s permission is needed to re-export the tanks because they were originally made in Germany, and it has been particularly cautious about making any move that could be interpreted by Moscow as a significant escalation. Politicians are also mindful of the country’s second world war history. Finland has said it is willing to donate Leopard 2 tanks alongside Poland, and the country’s prime minister, Sanna Marin, told the World Economic Forum it was necessary to support Ukraine in fighting off Russia for as long as necessary. “I think the only message that we need to send is that we will support Ukraine as long as needed. One year, two years, five years, 10 years, 15 years,” Marin said. On Monday, Wallace described the group of countries willing to donate the German-made tanks as members of “the Leopard coalition”. He urged “my German colleagues” to agree to the re-export. Moscow accused the west of waging a proxy war against it, as it announced plans to expand the size of its regular army to 1.5 million. The Kremlin spokesperson Dmitry Peskov said the rationale for the decision “stems from the war that the countries of the collective west are waging”. Russia launched its invasion of Ukraine on 24 February 2022 and it currently occupies about a sixth of Ukraine’s territory in the east and south, after 11 months of fighting. After Ukraine survived the initial onslaught last spring, the west has progressively stepped up its military aid to Kyiv. Scholz appointed a new defence minister on Tuesday, after the resignation of Christine Lambrecht. Boris Pistorius, the veteran interior minister of the northern state of Lower Saxony for the past decade, takes on the job just before Friday’s Ramstein meeting. Pistorius is a member of Scholz’s Social Democratic party but his appointment came as a surprise, not least because he has a low profile in Germany and is little known internationally. He has a reputation as a sharp-tongued, no-nonsense policymaker. The new minister is due to meet his US counterpart, Lloyd Austin, on Thursday. “I know the importance of the task,” Pistorius said shortly after his appointment. “It is important to me to involve the soldiers closely and to take them with me.” Robert Habeck, Germany’s economics minister, deputy chancellor and co-leader of the Green party in the governing coalition, said the new defence minister’s first crucial decision would be regarding the issue of tanks for Ukraine. Speaking on the sidelines of the World Economic Forum before the announcement, Habeck said: “When that person, the minister of defence, is declared, this will be the first question they will concretely have to decide on.”