Jean-Claude Juncker used his annual State of the Union address to try to heal rifts in the EU over his refugee policy as he acknowledged that the bloc was suffering an “existential crisis” following Britain’s shock vote to leave.

In his address to the European Parliament on Wednesday, Mr Juncker, the European Commission president, did not shy away from the problems confronting the European project — from “galloping populism” to national governments placing their narrow interests above the common good.

“Never before have I seen such little common ground between our member states. So few areas where they agree to work together . . . Never before have I seen national governments so weakened by the forces of populism and paralysed by the risk of defeat in the next elections,” Mr Juncker told MEPs, adding: “Our European Union is, at least in part, in an existential crisis.”

Mr Juncker’s speech was delivered with one eye on a meeting of EU leaders — minus Britain — in Bratislava on Friday to discuss a post-Brexit future for the bloc.

As well as urging national leaders to reinvigorate their commitment to the EU, Mr Juncker also offered a range of proposals to restore the bloc. One of his key plans is to seize the opportunity of Brexit to forge closer military co-operation in Europe, an idea to which Britain was always staunchly opposed.

Other measures he outlined included bulking up an existing €315bn EU investment programme, often referred to as the Juncker Plan, which supports lending to businesses. The new target is that it will lend at least €500bn by 2020.

Aside from the trauma of Brexit, Mr Juncker faces a more general backlash against the EU in many nations. At the same time, common action at European level has been rendered more difficult by the political schisms that have emerged among its leaders over years of dealing with successive crisis.

Before plotting the way forward, Mr Juncker tried to heal some of these wounds of the recent past, specifically those caused by the migration crisis. 

He offered an olive branch to countries in central and eastern Europe that have vehemently opposed a push by the EU to relocate refugees away from crowded camps in Greece and Italy.

Mr Juncker, a key architect of the refugee relocation scheme, said he would urge governments to find a way to reconcile those that were “reluctant to integrate refugees in their societies” with those who insist it is key to EU “solidarity”.

“I’m convinced much more solidarity is needed” on the refugee crisis, Mr Juncker said. “I also know that solidarity must be voluntary, it must come from the heart, it cannot be forced, it cannot be imposed.”

He also made an appeal to Poland, whose nationalist government has been engaged in a tense stand-off with Brussels over constitutional changes the EU fears undermine the rule of law — calling the country a “great nation”. 

The speech only briefly referenced the UK’s June referendum, in which British citizens voted to become the first EU member to leave the bloc. Mr Juncker refrained from repeating his demand, made repeatedly since the day of the referendum result, that Britain quickly begin formal exit talks — a stance rejected by Westminster. But he warned the UK that it would not be given “à la carte” access to the bloc’s single market.”

In addition to the enhanced co-operation on defence, other measures announced by Mr Juncker included a sweeping telecoms and copyright reform and further work to build a “capital markets union” that would break down barriers to cross-border investment.

In a less orthodox move, Mr Juncker touted the idea of a “European solidarity corps” — a pan-EU volunteer service for young people. He said that the scheme, to be up and running by the end of the year, would allow volunteers to offer their help during a crisis, such as this summer’s earthquake in Italy. He wants 100,000 young people to have taken part by 2020.

In addition to policy announcements, Mr Juncker mounted a staunch defence of a planned EU trade deal with Canada that is facing a backlash from politicians in several European countries, notably France and Germany, who fear it could allow multinational companies to trample on social and environmental rules. 

The commission president called the deal “the most progressive, the best trade agreement we have ever entered into” and said the EU would “look ridiculous” if it turned its back on an accord it had spent years negotiating. 

Gianni Pittella, the leader of the parliament’s Socialists and Democrats group said that Mr Juncker had provided “a credible programme for the next 12 months which are going to be crucial to our citizens”.

He said Brussels was seeking to act while national leaders “sleepwalk through the night”.

Philippe Lamberts, co-leader of the assembly’s Greens group, however, said Mr Juncker was failing to draw people to the European project.

“There was no passion, no thrust, no vision,” he told the FT, adding that the commission was “recognising that it can no longer determine a direction for the EU. It can’t force the member states.”