The two people hoping to replace Boris Johnson would rather not talk about Brexit

Rishi Sunak (L) and Liz Truss spar during a leadership debate on Monday in Hanley, England.

London (CNN)There's one thing that the two candidates locked in a bad-tempered battle to be Britain's next prime minister agree on: Brexit is nothing to do with any of the woes facing the UK right now.

That much was clear from an answer to a question the pair were posed in a televised debate last week, which came in the middle of gridlock at the approaches to the Port of Dover in southeast England, the gateway to the continent for millions of holidaymakers and a third of Britain's trade every year.
Liz Truss and Rishi Sunak -- the two remaining candidates to replace Boris Johnson as leader of the ruling Conservative Party -- were asked whether Brexit was to blame for the meltdown. Both answered emphatically: No.
    For Sunak, a committed Brexiteer, he could hardly have said anything else. But Truss, who campaigned for the UK to remain in the EU, has reinvented herself as a Brexit convert, no hint of heresy can be permitted. Both are locked in the battle to win over the members of the Conservative Party, who are among the most committed Brexiteers of anyone in the country.
      The inconvenient truth, as the head of the port of Dover has confirmed, is that Brexit has indeed contributed to the chaos. With the UK now relegated to third country status outside the EU, what was once a relatively seamless process at the border has been swapped for a significant processing burden with the potential for major hold-ups.    
      "We are in a post-Brexit environment, which means the transaction times through the borders are going to take longer because the passports need to be checked, they need to be stamped," Doug Bannister told LBC radio.
      Legal experts agree: "Pre-Brexit there was no requirement for your passport to be stamped," says Catherine Barnard, professor in European law at Trinity College, Cambridge. "This meant when things were busy at Dover, all you had to do was wave your passport. Finding a page and physically stamping a passport obviously slows things down and can really back things up," she adds. 
        Vehicles queue at the Port of Dover on July 22.
        And that's indeed what happened last week -- huge lines of trucks and cars which choked up roads in the county of Kent and caused misery for fed-up families stuck in their vehicles for hours.
        Yet the wannabe PMs' reluctance to speak ill of Brexit is unsurprising. It was their Conservative Party under Johnson that finally broke years of Brexit deadlock in 2019, winning a parliamentary majority in a landslide election on the promise to "Get Brexit Done" with an "oven-ready deal" that he'd personally secured after years of tortuous negotiations with Brussels. 
        But in 2022, things look very different. Brexit is far from being done, if the constant arguments over the Irish border and the chaos at Dover are anything to go by. 
        "While it is true that Brexit is done and the steps we have taken to leave the EU are irreversible, the consequences of Brexit remain," says Dominic Grieve, a former Conservative member of parliament who previously served as attorney general. 
        Those consequences extend beyond holidaymakers sitting in traffic and political meltdown in Northern Ireland. The Office for Budget Responsibility (OBR), the UK government's official independent economic forecaster, predicts that long-term productivity will be reduced by 4%, compared to if the UK had stayed in the EU. 
        The OBR also predicts that trade will be reduced by 15% in the long term and that new trade deals with non-EU countries "will not have a material impact, and any effect will be gradual."
        Brexit, the most significant political event in modern British history, has been notably absent from the discourse surrounding the race to succeed Johnson. Beyond vague references to taking advantage of Brexit's benefits and the candidates trying to one-up one another's Euroskeptic credentials, even the economic impacts are not being mentioned, despite the cost-of-living crisis that Britons are currently suffering. 
        There are undoubtedly things that the government can do outside of the EU that will provide economic benefits in some areas. Truss, in particular, is talking up the prospect of tearing up EU regulations that the UK has inherited from Brussels to free up cash that could be used to invest in British infrastructure. 
        "The government could roll back regulations around how things like pension funds and insurance are managed that would create the potential for that money being invested in infrastructure projects," says Vicky Pryce, former joint head of the United Kingdom's Government Economic Service.
        She adds, however, that "those benefits could well be outweighed by all the other negative things that may be happening in the short-to-medium term, like the lack of productivity hampering growth and the extra costs to businesses and consumers because of Brexit."