NIGHT time closures of the fire-damaged westbound M4 Brynglas tunnel look set to run for the next week.

Workers are installing temporary lighting in the tunnel after the previous system was damaged by lorry fire last Tuesday.

The blaze caused miles of tailbacks which lasted until Friday when a contraflow through the eastbound tunnel was lifted.

A spokesman for the Welsh Government said the first night time closure took place on Monday night.

Each closure will take place from 8pm, subject to traffic levels, and finish before 6am the next day.

There will be a diversion for the westbound tunnel northwards via the A4042.

The spokesman added: " We would ask motorists to take these works into consideration when planning their journeys and appreciate their patience."

The Welsh Government couldn’t give a final date for the works yesterday, but a spokesman said the work would take not take more than a week.

He couldn’t confirm last night whether there would need to be further closures in order to rectify the damage.

A 30mph speed limit was imposed through the westbound tunnel since the contraflow was lifted on Friday.

Gwent Police is working with the Vehicle and Operator Services Agency to investigate whether a mechanical fault in the lorry caused Tuesday’s fire.

The case was handed over to them by South Wales Fire and Rescue Service.

Investigators are examining the lorry and determining whether any mechanical fault or failure in the vehicle contributed to the fire starting.