Border Force has warned of a possible 'degradation of security' if Britain fails to secure a divorce settlement with the EU.

A leaked presentation suggested Britons could have to put up with bigger queues for the Eurostar and scores more migrants attempting to cross the channel in a 'no deal' scenario.

There is also likely to be a 'loss of data' and an 'additional clandestine threat, according to the report, which would come as a result of more distant security links with the continent.

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A leaked Border Force presentation details the likely challenges faced by the agency in the event of a 'no deal' Brexit

Under Border Force's no deal plans, UK citizens would no longer be able to use 'e-gates' when travelling to Europe - even though EU citizens would be allowed to use them when arriving in Britain.

The presentation, obtained by Sky News, is titled 'EU Exit assumptions - NO DEAL', and marked 'Official - Sensitive'.

A government spokesperson told the network: 'We do not comment on leaked documents.

'We have set our no-deal planning assumptions for the border in December and the government has been planning for some time for all potential outcomes.'

'Loss of data and access to a number of key systems' that 'we rely on' including 'some frontline operational capability' due to loss of EU systems under a no-deal Brexit.

Home Secretary Sajid Javid meets Border Force staff at Dover during the recent spate of migrant crossings from France

The presentation also reveals Border Force will have to rely on inferior Interpol data systems instead of the SIS2 database.

The document claims a no-deal Brexit 'would likely lead to disruption to commercial flight schedules, leading to flights arriving out of sequence and contributing to queues building at major airports [and] significant outbound queues at St Pancras [the Eurostar terminus]'.

Under a no-deal Brexit, Border Patrol officers reportedly also 'won't be able to differentiate between existing residents and new arrivals' from the EU/EEA.

And the document appears to suggest that even though the government will claim EU freedom of movement has ended, even new arrivals will be allowed to work and study.