Hertfordshire County Council has signalled that it is to review its street lighting policy – opening the way for streets in some areas to be lit until 2am.

Currently only street lights on the county’s network of ‘A’ roads and some other areas are lit throughout the night.

But in most areas the ‘part-night lighting policy’ means lights are switched off between 1am and 5am, after being progressively dimmed from 9pm.

Council officers estimate the policy – combined with the move to LED street lights – has saved £5 million a year on electricity costs.

They say it has cut carbon emissions due to street-lighting by 60 per cent - equivalent to 12,000 tonnes of carbon dioxide a year.

Now it has emerged the council is looking to make further changes to the system – that operates from a central control system.

Those changes could mean street lights are dimmed between 5am and 6am, reducing the cost to the council and the environment further.

And it could mean some streetlights are kept on for longer – until 2am – where there is ‘local justification’.

On Thursday (November 21) the approach was backed by members of the county council’s highways cabinet panel.

And, if approved by cabinet, council officers will then draw up a process to determine how requests for extended lighting would be determined.

That process is not expected to be considered by the cabinet panel until May 2020.

According to data presented to the meeting, dimming streetlights by 30 per cent between 5am and 6am could save the council £18,100 a year – and dimming by 50 per cent could save £30,200.

Meanwhile the cost of keeping streetlights on until 2am at 20 per cent power would cost around £17,000 a year,

At the meeting of the cabinet panel Liberal Democrat leader Cllr Stephen Giles-Medhurst pointed to a similar proposal suggested by his group in February – which was rejected by the Conservatives.

And he suggested 2am should become the default position, with justification needed to revert to 1am.

He also suggested plans to dim the street lights between 5am and 6am could be implemented immediately.

However executive member for highways and environment Cllr Phil Bibby rejected the calls for immediate implementation of the dimming proposals as a “knee-jerk reaction”.

And he said he did not believe there was an overwhelming requirement to turn the lights on until 2am.

He suggested that where a councillor identified a need, there may be a justification.

But he  said one man walking a dog between 1am and 2am would not fit the criteria of overwhelming need.

The county council’s street asset manager Peter Simpson said the preferred system would be for justification to be required to extend the lighting hours.

He argued a system where additional use of energy had to be justified would be better in terms of the council’s ‘sustainability’ aims.

It was also suggested that where a change was made, a further change would not be made for a further 12 months.

Lighting in Welwyn Hatfield and Three Rivers has not yet converted to the LED system. But this should be completed by March 2020.