I might have to walk more rather than drive and spend more on food. For a few weeks.
I think it might be a bit naive to believe that food prices will subsequently go down, tbh. And walking more is fine if you're able: I can barely walk to the corner shop while I wait for knee surgery, which will no doubt be a much longer wait if no-deal happens.
I also think that the document is very light on the knock-on effect of fuel shortages. What happens when people who have no other viable option can't get to work? Even if NHS and emergency services staff are prioritised, that still leaves masses of people that are essential for service delivery. How many organisations could still function if their IT staff couldn't get in, rural schools might have to shut if teachers can't get there, public transport may suffer.
And as DP pointed out last night, if payroll staff can't get in at the wrong time of the month, no-one gets paid. (He used to work for a large payroll bureau that had hundreds of clients, paying tens of thousands of staff: many of the bureau staff routinely did 50 mile commutes to work, and the firm is in a location that is poorly served by public transport).
I can work from home (as long as the internet/mobile networks are ok) and he can walk to work, but he has staff who won't be able to get in if they can't get fuel.
And the most populated part of the UK (SE) is going to be the worst affected, apparently.