European Commission leader Jean-Claude Juncker, along with the presidents of the European Parliament and European Council issued a joint statement claiming ‘any delay would prolong unnecessary uncertainty’.

‘We have rules to deal with this in an orderly way,’ the statement said. ‘Article 50 of the Treaty on European Union sets out the procedure to be followed if a member state decides to leave the European Union. We stand ready to launch negotiations swiftly with the United Kingdom regarding the terms and conditions of its withdrawal from the European Union.’

In a speech this morning, outgoing prime minister David Cameron made clear that Article 50, the first legal step in leaving the EU, would not immediately be invoked, meaning all existing laws and directives are still in force.

‘A negotiation with the European Union will need to begin under a new prime minister, and I think it is right that this new prime minister takes the decision about when to trigger Article 50 and start the formal and legal process of leaving the EU,’ Cameron said.

On the status of the New Settlement for the UK, agreed in February this year, the statement added: ‘As agreed, the New Settlement for the United Kingdom within the European Union, reached at the European Council on 18-19 February 2016, will now not take effect and ceases to exist. There will be no renegotiation.’

The statement also underlined that the UK remains an EU member state until the negotiations are completed, ‘with all the rights and obligations that derive from this’.

According to the treaties, EU law continues to apply to and in the UK until it is no longer a member.