Rishi Sunak will this week unveil new plans to stop “small boats” crossing the English Channel — but he faces a major fight in parliament and the courts to get them over the line anytime soon.

As part of efforts to curb cross-Channel migration, Sunak’s government will as soon as Tuesday publish legislation aiming to ban those arriving in the U.K. in the vessels from claiming asylum in the country at all.

“So make no mistake, if you come here illegally, you will not to be able to stay,” Sunak told the Mail on Sunday newspaper as he teed up the week. The PM has made “stopping the boats” one of his key priorities as he looks to reverse his party’s fortunes in the polls.

The new legislation is expected to try and make inadmissible all asylum claims of those who come to the U.K. on small boats. Under the plans, ministers would then remove from the country and permanently bar from returning anyone who used the crossing.

But the proposals — which also look set to throw up a political dividing line with the opposition Labour Party — already face a backlash, and there are questions about their feasibility.

‘Unworkable’

Labour leader Keir Starmer on Monday branded the government’s plans “unworkable,” and the party is calling them a reheat of previous pledges. It remains to be seen if the party will formally oppose the bill in the Commons.

But Starmer told LBC: “The problem has got to be dealt with — the crossings over the Channel. But this isn’t a workable plan.”

And he added: “We had a plan last year which was put up in lights … it was going to break the [people smuggling] gangs, it didn’t. Now we’ve got the next bit of legislation with almost the same billing — I don’t think that putting forward unworkable proposals is going to get us very far.”

Starmer was referring to the government’s Nationality and Borders Act, last year’s attempt to tackle the problem by bringing in a two-tier system which reduces the support available to asylum seekers who arrive in the U.K. by “irregular” means.

Ministers have also signed a controversial agreement to send asylum seekers to Rwanda, but none have so far been sent to the central African country amid legal challenges.

‘That’s not right’

Ministers hoped these proposals would deter those planning to make the treacherous journey across the Channel from France — but numbers crossing have not fallen since the Rwanda plan was announced last April. More than 45,700 people used this route to come to the U.K. last year, the highest figure since records began.

Sunak’s latest attempt can expect to face similar challenges in the courts and in parliament.

Asylum seekers have the right to seek protection under the U.N.’s Refugee Convention and the European Convention on Human Rights. According to weekend reports, ministers plan to legislate so that they can effectively circumvent both — something which would likely mire the government in legal difficulties.

“It will cause all sorts of difficulties,” Conservative former Brexit Secretary David Davis told talkTV Monday. “Just imagine an Afghan who was perhaps a translator for the British army, stuck in Afghanistan and wants to get here … [Under the proposals] he’s going to be excluded and indeed banned for 10 years if he comes across the channel. That’s not right.”

Sunak’s large majority in the Commons means any bill would likely pass even if Labour and a small band of Tories withhold their support. But there could be trouble ahead in the more finely balanced House of Lords, which demanded a host of changes to the previous legislation.

Campaigners meanwhile argue that, with the Rwanda plan on ice, Sunak – who meets French President Emmanuel Macron later this week — should be pressing for more safe and legal routes for people making the journey to the U.K.

“We can’t move anyone to Rwanda right now — it’s subject to legal challenge. We can’t remove anyone back into Europe because there are no returns agreements,” Lucy Moreton of the Immigration Services Union told the BBC Monday. “So, unless we have a safe third country that isn’t Rwanda to send people to, this just doesn’t seem to be possible.”

The U.K. has had no returns policy in place with the EU since its membership of the Dublin arrangements — which allowed Britain to return people who passed through a safe third country to be sent back — lapsed after Brexit.