City leaders have been accused of a string of failings which led to vital work to ease gridlock on the Chester Road overrunning by almost a year.

The major road improvement scheme around Spitfire Island has been beset by a series of "clashes" between council contractors and utilities and other agencies, it has emerged.

The ten months of delays to the Chester Road upgrade, in Castle Bromwich, has not only piled extra misery on commuters and motorists but added millions to the £11 million price tag of the works.

Birmingham’s Labour contracts boss Stewart Stacey admitted the scheme “hasn’t gone as well as might be hoped”.

“There’s a whole list of events and reasons for the delays. Most of them outside the control of the council and its contractors. There will be a lessons learned exercise," he said.

The M6 shot from the motorway

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The exact cost of the delays was not revealed in public but the Mail understands it runs into millions.

Opposition Conservative leader Coun Robert Alden (Erdington) said: “Not only has mismanagement led to extensive delays in the work that have cost residents time and money but also many of the problems should have been mitigated against.

“We have demanded the council carry out a review of their contracting process. These mistakes must not happen again.”

Work on the congested Chester Road includes widening approaches and upgrading traffic signals to improve traffic flows and journey times.

It began in June 2014 and was expected to be finished a year later. Instead, it is only now nearing completion - ten months behind schedule.

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According to a council report on the delays, there were “a number of unforeseen events”.

Perhaps most crucial was the road was designated as an official diversion route last year for traffic affected by works on the M6.

The report also talks of delays and "clashes" between contractors and the "statutory undertakers" - which could include gas, electric and water companies or government agencies.