New legislation to tackle small boat crossings in the Channel is likely to fall foul of the European Convention on Human Rights, Suella Braverman has told MPs.

Anticipating a possible legal fight, the Home Secretary wrote to colleagues saying there was a more than 50% chance the Illegal Migration Bill may be incompatible with convention rights.

But she said she was “confident” it did not breach international law and hoped the courts would take into account any endorsement Parliament gave to her “robust and novel” plans.

If the action was stalled by legal challenges, it would follow the much-criticised plan to forcibly remove asylum seekers to Rwanda in being currently grounded by the courts.

In a letter to MPs and peers shared with the PA news agency, Ms Braverman said she had had to make a statement under the Human Rights Act, which enshrined the convention rights in the UK.

“This does not mean that the provisions in the Bill are incompatible with the convention rights, only that there is a more (than) 50% chance that they may not be,” she wrote.

“We are testing the limits but remain confident that this Bill is compatible with international law.

“Both Houses will have an opportunity to thoroughly scrutinise the Bill and, once approved, the measures in the Bill will have been expressly endorsed by Parliament and we would expect the courts to take that into account.”

The right to a family life, freedom from torture and the right to a fair trial were all issues being considered as potential challenges to the legislation. So too was the right to liberty, with concerns over the powers for indefinite detention.

On the front page of the Bill, Ms Braverman acknowledges she cannot assure Parliament that the legislation is compatible with the convention but adds that “the Government nevertheless wishes the House to proceed with the Bill”.

The Law Society of England and Wales, which represents solicitors, said it would “carefully” analyse whether the plans impinge on access to justice as it issued a warning.

President Lubna Shuja said: “The Government has already conceded the Bill may not comply with international human rights law (European Convention on Human Rights) and questions remain about compatibility with the UN Refugee Convention.

“The rule of law is undermined if the UK Government takes the view that laws – international or domestic – can be broken. If a government breaks laws, it breaks trust with its own citizens and with international partners.

“We will be carefully combing the detail of this Bill to determine whether it will lead to the Home Office delivering a fair and workable process, and seeking clarity from the Government on whether it is compatible with the UK’s international obligations.”

Enver Solomon, chief executive of the Refugee Council, said: “It’s an admission by the Government that it’s in effect behaving like those countries that show disregard to international human rights conventions, the likes of Myanmar, Russia, Belarus.”

Ms Braverman alluded to the Bill’s “legal complexities” while announcing the plans in the House of Commons.

“Some of the nation’s finest legal minds have been, and continue to be involved in, its development,” she said.

Attorney General Victoria Prentis outlined some of the “legal measures” relating to the Bill to ministers during a Cabinet meeting earlier in the day.

Ms Braverman has previously called for the UK to leave the European Convention on Human Rights.

Prime Minister Rishi Sunak is resisting such a move, despite coming under pressure from the Conservative right.