NEGOTIATIONS on Britain's exit from the European Union should begin "as soon as possible", Germany's foreign minister has said after the bloc's six founding nations held emergency talks in the wake of the historic Brexit vote.

Frank-Walter Steinmeier said "intensive European discussions" are needed about the EU's future and called on Britain to engage in talks about its exit sooner rather than later. He added that Europe needed to be "able to carry out its work".

The core group of six comprises France, Netherlands, Italy, Belgium and Luxembourg - as well as Germany.

German Chancellor Angela Merkel echoed her minister, saying it "shouldn't take forever" for Britain to deliver formal notification that it wants to leave, but stressed there was "no need to be particularly nasty in any way in the negotiations". She added: "They must be conducted properly."

French foreign minister Jean-Marc Ayrault similarly called for quick talks on Brexit, saying there is "a certain urgency" in order to avoid "a period of uncertainty, with financial consequences, political consequences".

He said Britain should name a new prime minister in the coming days to speed up the exit process, hinting at a looming tension between the EU and UK leaderships. David Cameron has indicated that he would stay at Number 10 until October purely to "steady the ship", but wants his successor to handle the departure negotiations.

The UK's European Commissioner, Lord Hill, has already resigned, confirming yesterday that he would stay on a few weeks to ensure an "orderly handover" to Latvian politician Valdis Dombrovskis, who will replace him in charge of EU financial services.

Ayrault also urged the remaining 27 EU countries to return to "the spirit of the founders" of European unity, forged to prevent conflict via trade after the Second World War.

It comes amid fears that the UK shock referendum result will bolster support for euro-scepticism across the continent and trigger a domino effect as other nations demand the right to hold their own referendums on EU membership, potentially plunging the union into even deeper crisis.

Yesterday Slovakia's far right People's Party launched a petition for a referendum, saying it was "high time for Slovakia to leave the sinking European 'Titanic' as well".

The Brexit vote has already been welcomed by France's far-right National Front leader, Marine Le Pen - the front runner among candidates for France's 2017 presidential election - who called it a "victory for freedom". She added: "As I've been saying for years, we must now have the same referendum in France and other EU countries."

Notorious Dutch anti-immigration politician Geert Wilders said the Netherlands also deserved a "Nexit" vote, while Italy's far-right Northern League said: "Now it's our turn". Anti-immigration movements in Sweden and Denmark are also agitating to leave the EU.

However, Belgian foreign minister Didier Reynders countered, arguing that the result should spur further integration, not less. "We need to discuss with the UK the way out, but we need also to discuss how it is possible to do more with some partners or with 27 member states in different concrete fields," he said.

The president of the alliance of liberals and democrats in Europe, Guy Verhofstadt, highlighted Scotland's case to remain, saying that it was "wrong" that the country faced being pulled out of the EU despite 62 per cent of the population voting to remain, This followed First Minister Nicola Sturgeon's announcement that she would seek "immediate discussions" with Brussels to "protect Scotland's place in the EU".

Verhofstadt tweeted: "It's wrong that Scotland might be taken out of EU, when it voted to stay. Happy to discuss with Nicola Sturgeon next time she's in Brussels."

French president Francois Hollande expressed concern that the British vote posed questions "for the whole planet" about what would happen now.

But he vowed to maintain relations with Britain, notably about migrants crossing between the two countries and military and economic cooperation, and called for an orderly separation between Britain and the EU.

It came as the mayor of Calais called for migrant camps to be moved to Britain, stating the country must "take the consequences" of the decision to leave the EU. Natacha Bouchart said she will push for an end to the Le Touquet agreement which keeps border checks - and many migrants - on the French side of the Channel.