Tough new rules will make it harder for migrants convicted of serious offences to claim to be victims of modern slavery, under plans announced by the Home Secretary.

From Monday, the Government will be able to withhold protections from anyone sentenced to 12 months or more, or convicted of serious offences such as murder or terrorism, as part of a wider crackdown on illegal migrants.

The measures form part of the Nationality and Borders Act, coming with the Government under pressure from backbench Tory MPs in recent months to tackle small boat crossings at the Channel.

There have been 991 migrants crossing the Channel to the UK so far this year, according to Ministry of Defence figures.

It is totally unfair that genuine victims of modern slavery may be left waiting longer to receive the protections they need due to the flagrant abuse of the system

Home Secretary Suella Braverman said: “We must stop people exploiting our immigration and asylum laws. And I am personally determined to crack down on those abusing the generosity of the British public and taking our country for a ride.

“It is totally unfair that genuine victims of modern slavery may be left waiting longer to receive the protections they need due to the flagrant abuse of the system.

“The changes coming into force will mean if you’ve committed an offence, we have the power to refuse your protections and kick you out of our country.”

Previously, if a foreign national offender claimed to be a victim of modern slavery, any action to remove them would be paused while their claim was considered.

But from Monday, the Government will be able to prevent certain foreign criminals and anyone who has made false claims from accessing the protections provided by the National Referral Mechanism.

The Home Office said that guidance for case workers will also be updated, so that when reviewing a claim there should be objective evidence of modern slavery rather than “mere suspicion”.

Under the changes, the Government will also be able to withdraw access to the initial and any wider protections if someone has been found to have made a “bad faith” claim to be a victim of modern slavery or human trafficking.

The Home Office said that could apply where there is enough evidence to conclude that an individual has falsely claimed to be a victim of modern slavery – for example, if a story about their journey to the UK does not match immigration records.

The Modern Slavery Act was introduced by former prime minister Theresa May during her time as home secretary in order to protect vulnerable people from exploitation, domestic servitude or being trafficked for sex.

The Government has long warned about concerns that the current system is being abused, allowing offenders to remain in the UK.

Mrs May has been among those warning that a tightening of rules around modern slavery could create extra problems and undermine protections victims.