European leaders and officials have reiterated their criticism of Theresa May’s plans for leaving the EU, and warned the government against slashing taxes to attract business after Brexit.

Speaking at the World Economic Forum in Davos, the Dutch prime minister, Mark Rutte, said the UK would pay a “huge price” for prioritising immigration curbs over single market membership.

He said May’s announcement on Tuesday that Britain would leave the single market to be able to limit the number of people arriving from Europe at least showed she had “faced up to reality”.

But Rutte said the kind of Brexit deal the prime minister hoped to get would hit Britain’s economy hard. He said the UK was “making a choice … and paying a huge price because the economic growth rate of the UK will be impacted negatively by the fact that it will leave the biggest market in the world”.

Germany’s finance minister, Wolfgang Schäuble, said May would not be taken seriously by world leaders if she broke a G20 agreement by turning Brexit Britain into a low-tax competitor off Europe’s coast.

May made plain in her speech on Tuesday that she was ready to walk away from Brexit talks if Britain did not get what it wants from the EU. She suggested the UK would respond to any “punitive” deal by changing its economic model and reducing corporate taxes to attract investment.

But Schäuble, also speaking in Davos, said May’s claim to make the UK a “truly global Britain” after Brexit would be undermined if she used low corporate tax rates to compete with other nations, in breach of an agreement reached by world leaders at a G20 summit in Antalya, Turkey, in 2015.

“The UK has always agreed, and the G20 summit in Antalya said, that we will not use taxation of companies as … an instrument for competition – that has been agreed,” he said.

“If we want to be taken serious, we have to stick to what we have agreed. That has been agreed not in the EU, it has been agreed in the global forum of the G20, and a truly global economy has to stick to what has been agreed globally.”

After the Maltese prime minister, Joseph Muscat, reiterated on Wednesday that the UK’s Brexit deal must necessarily be inferior to EU membership, Pierre Moscovici, the European commissioner for economic and financial affairs, also said the UK should not think it will be able to keep the benefits of EU membership once it leaves.

Brexit was “not positive” for Britain or for the bloc, Moscovici told the BBC. He added: “It cannot be better to be out than in, because it cannot be so. You cannot have all the advantages of being the member of the club when you are out of the club. I think our British friends, who invented clubs, can understand that.”

Alexander de Croo, the deputy prime minister of Belgium, said “blatant lies” were behind the vote for Brexit, adding: “This was not even about fake news, it was fake argument … This is about blaming Europe for things that have nothing to do with EU policy.”

De Croo said he nonetheless agreed that “the pro-EU side was not able to counter that, because it countered it too much with facts and did not use emotion”.