There is a growing sense of frustration among some Kent MPs over the government’s proposals for a series of customs clearance sites dotted around the county as part of Brexit contingency plans.

A number met with treasury minister Jesse Norman and HMRC officials yesterday to press home their concerns about the unintended consequences of of these sites - five of which are in Kent - namely that they are likely to add to congestion and disruption and delays if there is a no-deal Brexit.

A key issue is that the sites are intended for inbound freight lorries - those that arrive in the UK via the Channel ports and Eurotunnel.

If they do not possess the right paperwork, lorries will be routed to these transit sites to get the necessary documents to allow them to continue to their destination.

According to the Ashford MP Damian Green, HMRC officials say that processing these foreign lorries could take between one or two hours.

He has repeated the point that access to the Ashford Truckstop off the M20 will be additionally complicated by by the fact that work on the new Junction 10A will not be completed by October 31.

Part of the difficulties that MPs have is that they are having to deal with two different government departments: the Treasury and the Department for Transport.

Concerns have been amplified by the leak of a Whitehall memo which suggests that the passage of lorries through the ports has been seriously underestimated precisely because of this issue.

According to the Financial Times which obtained the memo, the impact on what is described as freight fluidity is potentially far greater than the impact described in the recently published Operation Yellowhammer report.

One memo spells out that tailbacks outside Dover could stretch to around 150km. “Queues could reach a peak of 8,500 vehicles, a two-day maximum delay and a 1.5 day average delay,” it said.

Based on the length of a typical articulated lorry being about 16.5m long, a queue of 8,500 such vehicles would stretch for some 150km.

As with all all these forecasts there is an element of educated guesswork - the only reliable indicator of the ramifications will come when when we get to October.