A referendum for Greater Manchester residents will take place in December
A council has accused a bus company of censoring its attempts to encourage people to vote in Greater Manchester's congestion charge referendum.
Stockport Council, which opposes the charge, wanted to place its adverts on Stagecoach buses in the run up to the ballot - but the firm refused.
Council leader Dave Goddard said the company was censoring a legitimate information campaign.
Stagecoach said the adverts conflicted with its support for the scheme.
A £2.8bn package of investment in public transport, from the government's Transport Innovation Fund (TIF), is dependent on the introduction of the charge in 2013.
A massive publicity campaign is being waged by both sides of the yes and no debate ahead of the postal referendum in December.
Stockport council-funded adverts entitled "C-charge. Want to Pay? Have your say" would have adorned the length of Stagecoach buses on routes between Stockport and Manchester city centre.
But the company, one of the region's biggest bus operators, declined to carry the adverts.
Councillor Dave Goddard, said: "They are censoring an entirely legitimate and proper campaign to tell people in Stockport about the congestion charge, the impact of transport improvements on Stockport and to encourage people to vote in the approaching referendum.
"Stockport people deserve accuracy and clarity, and Stagecoach should be willing to be part of that.
"Their behaviour is disgraceful and has no place in a modern democracy."
Mark Threapleton, Managing Director at Stagecoach Manchester, said the company was within its rights to reject the advertising.
He said: "We believe that the TIF package has the potential to bring a host of improvements to public transport and the environment in Greater Manchester including more peak time buses, more reliable bus services and cleaner air quality for everyone in the area.
"We don't always accept all adverts we are requested to display and have universal policies on certain types of advertising including those which are not consistent with our beliefs on the future of public transport.
"We took the decision to carry our own adverts on our own vehicles and are therefore not accepting any other related adverts from third parties."
Stagecoach runs a number of services across the region, including the 192 service along the A6 between Stockport and the city centre.