Theresa May should admit her election disaster was a rejection of hard Brexit and let “everyone’s voice” be heard, the European Parliament’s negotiator says.

Guy Verhofstadt urged the Conservative Party to no longer allow “your internal catfight” to put prosperity at risk in both Britain and the EU.

Instead, the Prime Minister should pursue a relationship that is “as close as possible”, along the lines of Norway’s close links, or by remaining within the EU customs union.

“It is currently unclear if the UK Government will stick to the hard Brexit it announced in her letter of 29 March, or if they will soften their approach after the outcome of the election,” Mr Verhofstadt said. “In my humble opinion, the refusal of a hard Brexit was one of the elements that influenced the results.”

At a Brussels press conference, he urged Ms May to change direction, saying: “Brexit isn’t just about the Tories leaving the EU, it's about the whole UK. Everyone’s voice should be heard.”

And he told the Tory party: “For years now already, your internal catfight, that started under Cameron, has taken the EU hostage and has been hampering your as our economies. It is blocking us from further reforming and modernising the union. Frankly, we have seen enough of it.”

Mr Verhofstadt added: “I am impatiently waiting for the negotiating position of the UK Government that I hope will be more in line with the will and the interests of the British citizens.”

Association agreements already exist with more than 20 countries and could be achieved under Article 217 of the Lisbon Treaty, he said.

The call came as the European Commission’s negotiator warned Britain risks crashing out of the EU in March 2019 without an agreement on its future relations if it wastes further time on the Brexit talks. Michel Barnier urged Ms May to start talks very quickly and appoint a negotiating team that is “stable, accountable and with a mandate”, with time draining away.

Some Tory MPs argue that, with the clock ticking on the two-year Article 50 process, Britain must adopt “Norway option”, remaining in the European Economic Area with full access to the single market. But this would require Britain accepting at least some degree of free movement of EU citizens, which both the Conservatives and Labour have insisted will end.

Similarly, remaining in the customs union would make it impossible to seek separate trade agreements with non-EU countries.

Mr Verhofstadt said he was speaking on “the 30th birthday of the Erasmus programme”, the EU’s student exchange programme – which is threatened by Brexit.