Delivery drivers say they are being denied access to toilets at some service stations and petrol garages over coronavirus fears.
Cross Transport, which delivers to supermarkets, said drivers were being told to stay in their cabs when they arrive at distribution centres.
"We'll end up not getting deliveries done because drivers won't stand for it," manager Karl Starkey said.
The Secretary of State for Transport urged service stations to stay open.
In these extraordinary times, hauliers must be able to access roadside facilities to continue transporting essential items to supermarkets & our #NHS. I've asked motorway service stations to remain open (with special precautions in place) to ensure these vital journeys continue.— Rt Hon Grant Shapps MP (@grantshapps) March 26, 2020
The Road Haulage Association (RHA) said its members were being denied access because of fears over coronavirus.
It said drivers would normally use truck stops, motorway service stations or the facilities at distribution centres, but said it had received reports of drivers arriving at their destination to be told they cannot use the toilet or access showers.
Mr Starkey, who oversees operations at the Warwickshire-based firm, said: "It's getting worse, they need to be able to use the toilets.
"Even the garages are stopping them using them."
"Other drivers are complaining they can't use the facilities even at the distribution centres where they're going.
"They're not allowed into the buildings to use the toilets, they're all locked because of the coronavirus... they have to sit in their trucks."
He said his drivers felt like "second-class citizens", adding: "They're on the front line delivering the goods that are needed for supermarkets, they need to be there or you're not going to get the shops restocked."
Dean Cross, who owns the company, said demand had increased by "about 30%" in recent weeks and he has taken on extra trucks and trailers to "keep up."
The RHA said it was "keen to resolve the problem" and is working with the government.
A Department for Transport spokeswoman said: "Hauliers are vital to the nation's battle against Covid-19.
"Ministers have asked motorway service operators to stay open so drivers have access to crucial facilities."
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