British-based financial institutions must be prevented post-Brexit from selling their services in the eurozone, Emmanuel Macron, the likely progressive left candidate for the French presidency has told the Guardian.

He said a ban on so-called financial passporting rights, seen as potentially highly damaging to the City of London and one of the most fraught issues in Brexit talks, “should not be seen as a technical issue but a matter of sovereignty”.

Financial services passporting allows banks and other financial companies, like insurers and accountancy firms, to operate across the European Union based on their authorisation in a single member state.

Macron, currently the best prospect of preventing a rightwing victory in next year’s presidential election, added he could not see how the UK could be granted a financial passport unless it contributed to the EU budget in the same way as Switzerland and Norway.

But Macron insisted: “The financial passport is part of full access to the EU market and a precondition for that is the contribution to the EU budget. That has been the case in Norway and in Switzerland. That is clear.” The proposal would be rejected outright by British Eurosceptics.

He also gave no ground on free movement of EU workers, saying any concessions that allowed the UK to exclude some EU citizens would lead to the disintegration of Europe.

Macron’s remarks are a fresh sign that leading French politicians jockeying for the presidency are in no mood to offer concessions to the UK.

Macron,39, resigned from Hollande’s unpopular government last week, to set up new movement “En Marche” and assemble his “progressive diagnosis” of French ills ahead of a decision on a presidential bid in a couple of months. With only two years in mainstream politics, he is seen as an intriguing wild card who could thwart either Nicholas Sarkozy or the Front National of Marine le Pen.

He was in London to help build a campaign war chest as large as €12m (£10m) and claims 75,000 people have joined his movement since it was launched. Describing his position of third in the polls as “a good beginning”, he insists he can be the catalyst to disrupt and break the classical outmoded left-right political blocs.

Macron’s remarks on passporting run counter to claims made by both Philip Hammond, the chancellor and Boris Johnson, the foreign secretary, that passporting rights will be preserved. Hammond told MPs this week that any attempt by the EU to split off euro-denominated clearing would not benefit the EU, with business instead drifting to New York.

Johnson has insisted the UK’s financial services sector will not be stripped of the passporting rights, which exist within the single market, saying that the City of London will remain a global financial centre.

But Macron said: “We have the eurozone. Could we accept to be cleared, regulated and de facto have inflows and outflows from a country that has decided to leave the EU? For me, definitely not.”

He added the EU could not wait months and months for the UK to start Brexit talks. “Procrastination is not the right answer. We have to be extremely strict on the implementation of Brexit so there is a common approach between member states. We must avoid a sector by sector or country by country approach, and ask the UK to be clear.”

He also spurned the concessions on free movement as a price for access to the EU single market. “If you accept such caveats, the more you can damage the EU and it will be an open door for whoever has doubts about Europe, and so reduce the incentive to be pro-European.

“I was completely against the agreements signed with the UK in February; it just said ‘OK if you give me more, then I will stay in the club’. That is the beginning of the dismantlement of Europe. Now just because there is a leave vote, should we rewrite the rules of the club for one country. It’s a very strange defeat for Europe if people accept that.”

Macron said he is trying to develop a programme on economic dynamism, married to social protection, equality of opportunity and security: “I am not just a liberal movement. I come from the progressive left. I am trying to refresh and counter the system.”

Macron, attacking his rivals on the right on their strongest issue of national identity, described “the recent shortcut in the debate from the Nice terrorist attack to the burkini ban as crazy. A national debate on this was the best way to divide the country”.

He said that the middle classes were losing their sense of cultural security, but that issue could not be solved by national laws and bans.

“The guy who killed people in Nice was not a Muslim. Daesh [Islamic State] want civil war in our country. They want to divide the country. But they are not in a position to break our country unless we decide to enter into this game and organise a civil war. It is crazy to think the best way to defeat Daesh is to fight Muslims. We have 5.5 million Muslims in France”.

But he said there was a deeper issue about unintegrated Muslims in France, especially Salafists who regarded Islamic law as superior to French secular law. He estimated that between 25–30% of French Muslims, close to 2 million, thought in this way, and the answer lay in enforcing French secular law.

French Muslims had to become less dependent on preachers from Algiers and Morocco, he said. But he added that measures such as the burkini ban, or wearing the veil, risked disenfranchising Muslims and risking their ability to be fully aligned with the Republic.