Migrants who used the European Convention on Human Rights (ECHR) to dodge deportation last year will cost taxpayers nearly £5billion over their lifetimes, it was reported today.

Internal Home Office analysis found the cost of granting each asylum seeker the chance to remain in the UK because of their 'right' to a family life was £141,000 over their lifetime.

The calculation assumed they would pay taxes, the Daily Telegraph reported.

Nearly 35,000 arrivals were granted the right to stay in the UK under Article 8 of the ECHR, the right to a family life, in 2025.

It means the cost of funding their healthcare, education, welfare and pension bills is projected to hit £4.9billion, according to the analysis.

It is almost equivalent to the £5billion that Chancellor Rachel Reeves sought to cut from the welfare budget last year, but was forced to ditch the plans amid a Labour backbench rebellion.

The newspaper reported that the £4.9billion was an underestimate as researchers did not account for family members, writing: 'It does not include the fiscal impact of dependents associated with the cohort.

'It should therefore not be interpreted as the total fiscal cost of all individuals linked to Article 8 grants in 2025.' 

 It comes ahead of new planned curbs on foreign criminals' and failed asylum seekers' ability to use Article 8 to block their removal from the UK, to be unveiled in the Commons tomorrow.

Migrants can currently argue that being deported would be either unduly harsh because it separated them from their family, or that they would suffer by being uprooted and sent to a country that might be alien to their spouse or children.

It comes after a string of controversial cases emerged, including an Albanian criminal who dodged deportation partly because his son would not eat foreign chicken nuggets.

The Tories and Reform UK have vowed to quit the ECHR if they win the next election, saying it is necessary for taking back full control of Britain's borders.

However, Labour has insisted it's important to remain in the controversial treaty. Andy Burnham, widely expected to become the next prime minister within weeks, is also expected to make the case for remaining in the ECHR.

Robert Jenrick, Reform UK's spokesman on the economy and former Tory immigration minister, said: 'The ECHR allows dangerous foreign criminals to stay in our country – and now it's clear it's also costing the country a fortune.

'The Tories refused to leave the ECHR, despite myself and others campaigning to do so. Only a Reform government led by Nigel Farage will do what is required to restore sanity to our immigration system.'

The projections assumed each migrant will start in a low-paid job on a wage of £19,619, with up to a third potentially unemployed. It subtracted what they are expected to pay in direct income tax and indirect taxes such as VAT.