The Department for Transport currently wants road hauliers to trial lorries weighing 48 tons to transport goods from rail freight depots to distribution hubs.
And it is considering whether to do trials of 60-ton lorries which are 82ft 8in long (25.25m), compared to the current maximum of 54ft 6in.
The trials are to evaluate how longer and heavier vehicles can cut congestion and pollution by having fewer lorry journeys.
But the plan has horrified some transport campaign groups.
Norman Baker, of the Campaign for Better Transport, said increasing weight limits led to more lorries, increased carbon and air pollution, and higher road repair bills.
He added: “It’s not a sensible policy.”