France has triggered a €50m (£44m) plan for a no-deal Brexit after the UK parliament’s overwhelming rejection of Theresa May’s deal, the French prime minister, Édouard Philippe, has said.

“What’s certain is that the scenario of a no-deal Brexit is less and less unlikely,” Philippe told reporters in Paris after a meeting with ministers on Thursday, adding there were “strong fears” Britain would leave without a deal on 29 March.

“In such conditions, the government’s responsibility is to make sure the country is ready, that the interests of our citizens are preserved … That’s why ... I have decided to trigger the plan for a no-deal Brexit.”

Theresa May survives vote, but Britain remains in Brexit deadlock Read more

Five decrees will be issued “within the next three weeks” including authorisation for major investment in new infrastructure such as border control checkpoints, roads, lorry parks and warehouses at the ports and airports “most concerned” by the prospect of no deal, Philippe said.

Authorities will also start hiring 600 extra government employees to deal with the consequences for cross-border trade of the UK leaving the EU without a deal, including customs, veterinary and other inspectors to carry out the necessary checks on goods, livestock and food products.

“We want to be ready,” Philippe said. “This plan incorporates legislative and legal measures aiming to ensure … that the rights of both our fellow citizens and our businesses are effectively protected.”

He added that France would also take steps to secure the interests of its fishing and fish-processing industries.

The French parliament this week approved a law allowing the government to impose emergency measures by decree if necessary to cope with the consequences of a no-deal Brexit, including steps to “stabilise” travel, residence, work and welfare rights for British citizens in France, who would have 12 months to apply for permission to stay.

A no-deal Brexit would be “dramatic”, said Jean Bizet, the chair of the French senate’s European affairs committee, which on Tuesday heard from Gina Miller, the campaigner whose supreme court case forced the government to win parliament’s backing before it could trigger article 50, kickstarting the two-year Brexit process.

Miller said she thought the most likely outcomes were a Norway-style, very soft Brexit or no deal. A people’s vote or second referendum was much less likely, she said.

“It’s almost impossible to say and, despite the short length of time left, almost too early to say. But any outcome is now in the gift of MPs and from what I’m hearing only about a third back a people’s vote. So if you go by that we’re a long way off.”

Miller said the main obstacles to a people’s vote were practical, organisational issues: “An extension of article 50 would not be enough, it would probably require revocation,” she said. “You’re talking nine to 11 months. It’s not realistic to expect the EU to go along with that” without revocation.

Theresa May has left it far too late to start working on reaching a cross-party consensus on a form of Brexit that might be acceptable to parliament, she added, and a lot now rested on the Labour party’s response. “The Labour frontbench has to come off the fence and make a decision,” Miller said.

“It has to move to something. I think it could be Norway – it’s very hard for them as a Norway-plus relationship doesn’t satisfy their six tests. At the moment, I’d say we’re poised 50-50 between Norway and a no deal.”