Opponents of Britain's only privately-run toll road have criticised the operator's decision to raise charges for motorists for the first time.

Standard day rates on the M6 Toll for motorbikes and cars increased by 50p to £2.50 and £3.50 respectively and charges for vans and HGVs increase by £1 to £7 yesterday.

The price rise is an effort by operators Midland Expressway Ltd to persuade regular users to join the road operator's discounted Tag scheme.

The above-inflation rises are the first since the £900 million, 27-mile route opened in late 2003.

Business leaders in Birmingham recently called for the Government to step in to regulate prices on the toll road to protect consumers and encourage more hauliers to use the road.

Tom Fanning, MEL managing director, said Tag accounts, saved motorists five per cent of the toll on each journey.

" The road has always offered value for money as a free-flowing alternative to the congested M6," said Mr Fanning.

"Let's not forget that we have spent more than £900 million on delivering this road with no drain on taxpayers' money.

"I believe the lorries that have used the road in the past will continue to use the road.

He added: "There are no plans to review the standard toll prices again during the next 12 months.

"This new discount for Tag account holders rewards our most loyal customers and provides even greater value for money.

"Since we announced the discount, applications to open Tag accounts have increased by more than 50 per cent compared with the same period last year. All existing and new Tag customers will benefit from the discount scheme."

The Tag is fitted to a vehicle's windscreen and allows drivers to pass through a toll station without stopping to pay by cash or card.

The M6 Toll has dedicated Tag Lanes and Tag account holders can access their account details online 24 hours a day.