Fines for drivers who did not pay to go over a bridge may not be enforceable as the wrong word was used to describe the crossing fee, a tribunal has ruled.
A Traffic Penalty Tribunal (TPT) appeal ruling said drivers do not pay a toll to cross the Mersey Gateway, as is stated by Halton Borough Council.
Instead, they pay a "road user charge", which is legally different, it said.
The council said it would review the decision, but added it was "business as usual" for drivers on the bridge.
The appeal was brought by Scrap Mersey Tolls (SMT) campaigner Damian Curzon.
He argued there were errors in the wording of two penalty charge notices (PCNs) he received for failing to pay the £2 crossing charge on 15 June 2018.
'Wrong in law'
The TPT adjudicator said referring to the "non-payment of a 'required toll'" breached 2013 Regulations under the Transport Act 2000 and made the PCNs issued "defective".
He said the notices should have stated that "the penalty arose as a result of not paying a road user charge".
His conclusion also cited other "procedural improprieties" that rendered the fines unenforceable, including the same wording being used in bridge signs.
A TPT spokesman said the findings would be "taken into account when [the adjudicators] are considering other appeals made in respect of the scheme".
A council spokesman said the authority would continue "to enforce tolls", adding that the ruling "does not have general effect" and any suggestion that it was "acting inappropriately or illegally is misleading, inaccurate and wrong in law".
He also said the signs comment "contradicts" an earlier decision by the TPT, which said it was "large, well sited, in clear view, and [able] to communicate to a driver... that a payment was required".
A SMT spokesman said the council had turned the law "upside down" and tolls could not now be enforced "unless Parliament changes the current law".
Millions of £2 charges have been paid by motorists since the £600m bridge, which became the second crossing between Runcorn and Widnes, opened in 2017.