Warning signs on controversial bus lane cameras which have issued more than 80,000 fines to drivers in Birmingham might not be legal, the country’s traffic watchdog has warned.

The Traffic Penalty Tribunal has called on Birmingham City Council to defend its controversial city centre bus lane cameras amid suggestions that warning signs do not meet government rules.

In a letter to the council’s transport department Stephen Knapp, of the Traffic Penalty Tribunal, asks officials to explain why certain signs do not, on first evidence, appear to comply with Department for Transport traffic signs regulations.

In one comment he asks why a sign has been used without markings on the carriageway, as required.

Mr Knapp is due in Birmingham on February 12 and 13 to hear a large number of appeals over the controversial city centre bus lanes enforcement cameras which between their introduction in September and mid-December issued 80,000 tickets to drivers, with fines of £60 halved if paid promptly.

He has also decided to take a walk around the enforcement zone “to make a judgement about whether the signing of this bus restriction is adequate”.

The majority of drivers have been snapped by the camera southbound in Priory Queensway – with dozens of motorists complaining they could not see the signs early enough to avoid the lanes without performing dangerous manoeuvres.

Many of those snapped have been visitors to the Children’s Hospital and were caught turning left.

Even the council’s own transport watchdog committee described the enforcement as ‘unfair’ and called for a rethink.

A businessman who frequently hosts training events in Birmingham told the Post he was now looking for venues outside the city after being unfairly snared in the controversial Priory Queensway bus lane.

Manchester-based Richard Stone, who organises training sessions, says he has already re-arranged several meetings away from Birmingham city centre since being sent a penalty notice.

Mr Stone said: “I turn into Priory Queensway. At that point I see the bus lane and see the right filter lane. I pull into the right filter lane but was incredibly confused as it looked like I would have to go into a private car park.

“Thinking that couldn’t be right and also sure that the council wouldn’t be encouraging motorists to perform U-turns into oncoming traffic, I confusingly drove down the road, obviously going down the bus lane.”

He added: “Therefore the plans have had the desired effect of clearing the roads as me and my colleagues have gone elsewhere meaning that we haven’t spent money on meeting rooms in Birmingham, car parks, restaurants and hotels. I wonder how many other people have made the same choice.”

Greater Birmingham Chamber of Commerce said that while Birmingham-based business people had not made significant complaints they are concerned if outside visitors are being put off.

Spokesman John Lamb said: “We are not aware of complaints from our members, but most will be aware of the bus lanes through the publicity. But it is a great shame if they are deterring visitors. I hope common sense will prevail.”

Pressure is now building on the Cabinet member for transport Coun Tahir Ali (Lab, Nechells) to refund tickets and beef up the signs to leave motorists in no doubt they are entering a bus lane.

Earlier this month £1 million in fines were cancelled or refunded in Colchester after Essex County Council agreed its bus lane warning signs were inadequate .

One of those taking his case to tribunal is Sutton Coldfield pensioner Ben Cheney who set up his own facebook campaign page called Ben Fighting The Birmingham Bus Lane Fines.

Mr Cheney said: “I don’t mind if I end up paying the £60 fine but I am deeply concerned that young families returning from the Children’s Hospital are being trapped and fined because of what everybody regards not as a bus only lane system but a deliberate money earner for the council.”

But so far the council’s transport department, which by December had made £1.7 million from the fines, has refused to back down. And despite agreeing to review the scheme in January, no details of the review have yet emerged. A spokeswoman said that the council’s position has not changed.

Coun Ali has been bullish on the fines, saying that people who drive in bus lanes are breaking the law .

He has previously said: “We have people blatantly driving in bus lanes. We have big symbols on the road and on the lampposts. They are not taking notice and should expect a fine.”