Speaking in Brussels at the end of the first day of a European Council meeting exclusively devoted to Brexit, Costa said that "it was necessary to find a solution" that on the one hand prevented a disorderly exit next Friday, 29 March and, on the other, avoided possible disruption of coming elections to the European Parliament the functioning of EU institutions.

"With the decision that was made today, I believe that we responded positively to what we needed to respond to," he said, noting that the UK’s request for an extension to 30 June was not accepted. Instead an "extension in two modalities was agreed": that is, an extension to 22 May, assuming that next week the UK parliament approves the existing exit deal, or an extension to 12 April if it rejects it once more.

Costa explained that 22 May was chosen as the eve of the first day of voting for the European elections – which take place in EU member states from 23 to 26 May – given the need to rule out any legal problems relating to the UK taking part or not.

By 12 April, the government in London must decide whether or not to take part in the elections. If the UK communicates its intention of doing so, then the extension granted to no later than 22 May may be prolonged.

Costa further stressed that "the European Council reaffirmed with all clarity that it is not available to reopen negotiations on the exit agreement: there is no plan B: either it is approved, or it is rejected."