Rishi Sunak's hopes of finally getting Rwanda deportation flights off the ground could be undermined by migrants absconding 'en masse', Tory critics claimed last night.

They raised the alarm that the entire policy could be scuppered by illegal migrants simply disappearing before they were flown to the East African country.

The claims came as even the Home Office's own private guidance appeared to raise fears of an increased risk of illegal migrants on bail disappearing and potentially avoiding being traced.

Last night, Home Office sources voiced confidence that the Rwanda policy would work.

Rishi Sunak's Rwanda plan could be scuppered by illegal migrants simply disappearing before they were flown to the East African country, critics claim

A leaked Home Office document seen by the MoS warned of 'issues across the bail process which will increase absconcion [sic] and hamper tracing efforts'. Members of staff board a plane to transport migrants to Rwanda

The row broke amid expectations the much-delayed Safety of Rwanda Bill, paving the way to Channel migrants being sent to Africa, will finally become law this week. Ministers have sought to blame Labour for the delay and scuppering the Prime Minister's hopes that flights would be up and running 'by the Spring'.

However, some senior Tory MPs – including former Immigration Minister Robert Jenrick – have repeatedly warned that the current draft legislation contains too many loopholes to be effective.

And a leaked Home Office document seen by the MoS warned of 'issues across the bail process which will increase absconcion [sic] and hamper tracing efforts'. Marked 'Official – Sensitive' and dating from last year, it warned that even if a migrant was bailed to an address, 'operational pressures, and non-compliant behaviour' could limit the information collected on individuals.

Some senior Tory MPs – including former Immigration Minister Robert Jenrick (pictured) – have repeatedly warned that the current draft legislation contains too many loopholes to be effective

It said that although a migrant who absconded was 'referred to Immigration Enforcement to be located', there was a risk that 'capacity to trace people is outstripped by demand'.

It added: 'The time elapsed between losing contact with individuals and initiating efforts to locate them can be lengthy. The less time a person has spent in the UK, the smaller their footprint.'

Tory MP Paul Bristow said it would be a 'great shame if migrants being able to abscond en masse undermined this policy'.

Sources close to Home Secretary James Cleverly hit out at critics who 'have a vested interest in this Bill failing – otherwise, they're proved wrong', adding: 'And they're as worried as Labour are that that's going to happen.'