The door on the European single market would be permanently closed to Britain should the nation vote to leave the European Union, the German finance minister Wolfgang Schäuble said.
Speaking to influential German political magazine Der Spiegel, Schäuble ruled out the possibility of Britain following in the footsteps of Norway and Switzerland, both of which enjoy the benefits of the single market despite not being EU members.
Earlier this week, pro-European MPs floated the idea of using the Conservative government's small majority to push for the UK to stay in the European single market, even if the public vote to leave the European Union.
Unnamed MPs have said that if there were a Brexit vote, pro-EU MPs, who comprise 70% of Commons' members, could justify the move because the Leave campaign has not explained what trading relationship it wants the UK to have with the EU.
However, the German finance minister swiftly dismissed the possibility, claiming Britain would be out of the single market should the 'Leave' campaign prevail on 23 June.
"That won't work," Schäuble told the weekly in an interview which is set to published on Saturday that was seen by the Guardian. "It would require the country to abide by the rules of a club from which it currently wants to withdraw. If the majority in Britain opts for Brexit, that would be a decision against the single market. In is in. Out is out. One has to respect the sovereignty of the British people."
Should Britain leave the 28-country bloc, pro-EU ministers are expected to try and keep Britain in the single market, which guarantees the free movement of people, goods and services, by joining the European Economic Area (EEA).
Non-EU countries such as Norway, Lichtenstein and Iceland are members of the EEA, while Switzerland has retained access to the single market, despite not being a member of either the EU or the EEA.
Eurozone policymakers have repeatedly warned about Brexit and, until recently, were understood to be open to come to an agreement with Britain to ensure the latter remained in the EEA. However, Schäuble's stance looks to have hardened considerably.
"Europe will also work without Britain if necessary," he said. "At some point, the British will realise they have taken the wrong decision. And then we will accept them back one day, if that's what they want."
Germany's finance minister added that should Britain vote to remain in the 28-country bloc, the EU could draw lessons from the referendum.
"In response to Brexit, we couldn't simply call for more integration," he told Der Spiegel. "That would be crude; many would rightfully wonder whether we politicians still haven't understood.
"Even in the event that only a small majority of the British voters reject a withdrawal, we would have to see it as a wake-up call and a warning not to continue with business as usual. Either way, we have to take a serious look at reducing bureaucracy in Europe."