The big question: Is this happening at airports all over the country?

JAMES Cleverly will not be happy to wake up to yet another immigration crisis this morning.

Already tasked with resolving two huge issues – Channel small boats and record net migration – the Home Secretary is now facing calls to look at the solidity of Britain’s border controls at airports up and down the country.

Glaring shortcomings in passport controls which are highlighted by the borders watchdog in the Mail today may be replicated at every airport which accepts private jets and chartered aircraft, including major hubs such as Heathrow.

The key concern at this stage is that the scale of the problem is unknown.

London City airport received 1,305 private or chartered aircraft last year, of which 687 were classified by the Border Agency as ‘high-risk’, a watchdog said.

The agency’s staff are supposed to carry out face-to-face checks of 100 per cent of high-risk flights, but did so in just 21 per cent, according to figures disclosed by Independent Chief Inspector of Borders and Immigration David Neal.

The Home Office disputed the breakdown of high-risk and low-risk flights last night, but was unable to provide a revised tally.

The figures disclosed to Mr Neal mean the occupants of more than 500 private aircraft were allowed to leave the airport, and enter Britain, without having their passports scanned. It will never be known who was aboard those planes.

Mr Neal, rightly, has major concerns and has taken the unusual step of going public with them. His fears are that in the absence of any security checks, undesirables may have been able to come into Britain – and be able to remain here for good.

Shoddy security may have been exploited by organised crime gangs wanting to get personnel, trafficking victims or contraband into this country. It also opens up the prospect that foreign nationals with no right to come here may have been aboard some of the flights. It may also have been open to abuse by extremists or enemy states.

The new scandal echoes a fiasco in 2011. The then head of border controls, Brodie Clark, resigned after it emerged that parts of the arrivals hall procedures – including scans of biometric chips and checks against security databases – had been abandoned during busy periods in order to reduce queues.

THE then-home secretary Theresa May placed the blame squarely at the door of Mr Clark, telling MPs he ‘authorised the wider relaxation of border controls without ministerial sanction’. ‘As a result of these unauthorised actions, we will never know how many people entered the country who should have been prevented from doing so,’ she added.

Mr Clark sued for constructive dismissal and in March 2012 the Home Office announced it had agreed a six-figure out-of-court settlement with him.

Just as in 2011, it is the unknown implications of the new borders blunder that pose the greatest concern. How many people were aboard those unchecked aircraft? Who were they? How long has this been going on?

And is it happening at airports around the country, not just London City?

These questions are unlikely to receive prompt answers given that Mr Neal will leave his post in just over four weeks, after the Government declined to renew his tenure.

The chief inspector had already repeatedly voiced his frustration at the Home Office for failing to publish his inspection reports in what he described as a ‘timely fashion’.

Thirteen reports – including ones which look at the asylum casework process and how the department tackles illegal working – are languishing in the Home Office’s stockpile, awaiting a publication date. The oldest dates back to last April.

As immigration shapes up to be a key battleground in the general election, the Government will be keen to avoid opening up a new front. It will hope that any security botches were introduced without ministerial authorisation, putting them in the clear.

But the Home Secretary will know that today’s revelations make it even more difficult for his party to demonstrate this island’s borders are safe in its hands.