The scale of disruption predicted to hit UK borders post-Brexit is revealed in confidential government documents warning of queues of 7,000 lorries in Kent, and two-day delays to cross into the EU. A “reasonable worst-case scenario” report, drawn up by the Border and Protocol Delivery Group, forecasts that thousands of passengers could also be forced to wait an extra two hours for Eurostar trains. Dated last week and seen by the Guardian, the 46-page document marked “official – sensitive” says that a core IT system for hauliers is not expected to be tested publicly until the end of November. With the UK leaving the customs union and the single market on 1 January, it means that border disruption could ensue whether or not the UK secures a trade deal with the EU. The document was presented to a meeting of the XO (exit operations) committee chaired by Michael Gove for decisions on the next stages of development in the border operating model, the goods vehicle management system and so-called “smart freight” software designed to regulate the flow of traffic into Kent and guard against congestion. It notes that preparations for new post-Brexit border operations are all-consuming, affecting 26 government departments using 100 IT systems. Some departments legally cannot share data with others, with legislation required to ensure information flow, the report says. On road haulage, it forecasts that 50-70% of large businesses will be ready for cross-border trade. When it comes to smaller businesses, it assumes that as few as 20-40% of small- to medium-sized businesses will know what to do from 1 January. In the reasonable worst-case scenario, in which 30-60% of lorries carrying freight are ready, Kent would be plunged into chaos, bringing disruption to businesses across the country. “It is estimated a maximum queue of 6,500 HGVs may develop in January,” the report says. “Disruption could be lower in the initial days of January but we would expect sustained disruption to worsen over the first two weeks as demand builds”, with people returning to work after the Christmas and New Year holidays. “Considering demand levels in the first week of February, it is estimated that if readiness does not improve by then, queues could reach a length of 7,000 HGVs. In each case it is estimated that HGVs could take two days to reach the front of the queue,” it says. Kent authorities have rebooted Operation Fennel, with contingency plans to cope with the queues, it adds. But their efforts will be frustrated unless the smart freight system – a web portal operating a red, amber and green traffic light system for hauliers – is working on time. Only those given the green light, after passing a documentations test, will be given a Kent access permit. The document reveals the system will not go into a public beta testing phase until the end of November, leaving little time to launch it fully or train drivers and their customers. “Smart freight is all great in theory but how are they going to weed out the drivers who haven’t got the green light?” said an industry source. “Even if they use automatic number plate recognition technology, how are they going to stop trucks just driving into Kent thinking they will finish the paperwork when they get there? Do they have enforcement officers pulling people over? Do all trucks have to go to a lorry park for clearance? This is why you hear people talking about a border within Kent. But these questions have not been answered by the government yet.” The report piles pressure on the government to decide and publicise plans for lorry parks across the country where support can be provided in the early days. So far it has only confirmed one, in Ashford in Kent, with legislation passed on 4 September to give powers to build others in 29 council areas. It calls for advice centres to be set up across the country, with 39 sites identified at truck stop and service stations on all main motorways including the M6, M40, M1 and M20. These should be equipped with printers to help hauliers who do not have the right documentation prepare for their onward journey to ports in Kent, Portsmouth, Holyhead and Felixstowe among others, it says. But insiders say if they don’t also have customs clearance at these sites then “there isn’t much point to them”. With fewer than four months to go before the end of the Brexit transition period on 31 December, the document also notes that ongoing work at the Department for Transport to provide the advice centres “is currently unfunded” with a parallel treasury bid for £18.5m still in development. It recommends that a “Border Impact Centre (BIC)” is set up by 31 December to help national and local authorities get to grips with the change in border-destined traffic. Technical discussions with France may not start until the end of September, although the document explores the option of Kent authorities co-locating with France’s “Lille crisis cell” to jointly manage the potential chaos on the roads. Passengers on Eurostar and at airports could also face “significant disruption” if UK nationals are not allowed to use e-gates. This would not be the default in a no-deal scenario. Modelling from last year indicated that new border controls at the Eurostar gates at London’s St Pancras station “could lead to queues of many thousands”, the document says. It adds that Eurostar “has committed to mitigate this scenario, including in extremis cancelling services”. A Cabinet Office spokesperson said: “As a responsible government we continue to make extensive preparations for a wide range of scenarios, including the reasonable worst case. This is not a forecast or prediction of what will happen but rather a stretching scenario. It reflects a responsible government ensuring we are ready for all eventualities.”