Downing Street has suggested it will not always routinely release details of Boris Johnson’s calls with world leaders, after failing to disclose a number of calls with European leaders over the vaccine export dispute. There have been negotiations between the UK and EU as No 10 seeks to avoid escalating tensions over the export of vaccines from an AstraZeneca facility in the Netherlands. Officials in Brussels said they would probably block an export application from the plant if one were made. Johnson called the German chancellor, Angela Merkel, and the French president, Emmanuel Macron, on Sunday, according to UK and European sources. Merkel has since urged the EU to be “very careful about imposing blanket export bans, and you have to look very carefully at the supply chains”, and stressed that EU leaders would “seek dialogue” with the UK government. At a summit of European leaders on Thursday, the EU is likely to widen criteria for possible Covid vaccine export bans, including taking into account the level of vaccination coverage in a country such as the UK, and its record in facilitating exports to the bloc, when deciding on whether to prohibit individual vaccine shipments. One Whitehall source said on Monday there had been early talks on what the UK could offer to avoid a major international dispute, including the possibility of sharing supplies from the plant. It is usual for Downing Street to release official readouts of the prime minister’s calls with world leaders as a matter of public record, with officials present on the calls in order to release some details about what was discussed. The prime minister’s official spokesperson said when asked about the secrecy of the calls that he did not “have anything to set out today in terms of calls”. It is understood No 10 has deemed the calls to be private conversations, despite them concerning government policy. “The PM regularly speaks to the EU and European leaders as he did last week and over the weekend,” a No 10 spokesperson said. Allegra Stratton, the prime minister’s press secretary, said future calls would be disclosed if “a decision is taken” to do so.