Parking wardens began their second week-long strike of the year in their ongoing dispute with contractors NSL on Wednesday,

as Camden Council admitted it paid “over the odds” in sub-contracting out parking enforcement.

Parking enforcement officers have been picketing outside the Town Hall after representatives at UNISON failed to reach agreement in their increasingly bitter dispute with NSL.

UNISON branch secretary George Binette spoke at a council meeting on Wednesday night to urge Camden to intervene with NSL and to bring the wardens back into full public sector control.

With 130 wardens out on strike, NSL are believed to be shipping in workers from other parts of the country to prevent a parking “free for all” in the borough.

NSL has become the leading player in parking enforcement in the UK, making an estimated £18.1 million profit last year, and generating £24 million in ring-fenced revenue for Camden Council through issuing parking fines.

Basic pay for NSL workers in Camden now stand at £8.92 an hour, which is below the London Living Wage (LLW) of £9.15, although the council has subsidised NSL since spring of this year to meet the LLW.

Mr Binette said: “I presume that NSL has been banking the difference and perhaps building up a war chest in anticipation of an industrial dispute.”

Wardens are able to make more than the LLW if they achieve a bonus payment of £83 per month for full attendance and punctuality, but this is not guaranteed.

The dispute now centres purely around the hourly rate of pay after NSL refused to negotiate on working conditions or altering the length of the working week, which is currently 42.5 hours.

Mr Binette told the council: “These workers face daily abuse, often overtly racist, and even when physically attacked on the job there is no guarantee they will automatically get occupational sick pay.

“Please intervene with NSL. Use everything within your powers contractually to make sure this company is penalised for penalty charge notices that are not issued and for failing to meet their Key Performance Indicators (KPIs) for person hours on the streets.”

Cabinet member Merik Apak said he recognised Camden UNISON had made “valiant efforts” to resolve the dispute without recourse to strike action.

He said: “This is no time for face-saving or for posturing. The council has paid over and above for this contract to cover the living wage. We have been pressing NSL and shall continue to do so.

“When the contract comes to an end, the council shall consider all options, including bringing the contract back in house. But for the here and now, I urge all parties to lock themselves into a room and to resolve this dispute as quickly as possible.”

NSL failed to respond to requests for comment.