The imminent changeover to British Summer Time may cause problems with streetlights, residents in south west Hertfordshire have been warned.

Hertfordshire County Council said it expected some lights may fail to come on when the clocks go forward an hour on Sunday March 30.

Hertfordshire’s streetlights first started malfunctioning in 2012 after the council implemented its money-saving switch-off scheme, which sees thousands of lights turned off between midnight and 6am.

Initially the issue caused large numbers of streetlights to cut out leaving many streets in the area in darkness.

At the time the cause of the problem was identified as an issue with the lights’ photocells, which control the timed switch-on, and thousands had to be replaced.

This week, the Conservative-run council blamed the ongoing issues on its contractor, Amey Lafarge, who it said will be expected to fix any malfunctioning lights at its own expense.

Terry Douris, the council’s cabinet member for highways, said: "We continue to work with the contractor - Amey Lafarge - who supplied the part-night streetlight timing devices to get them to resolve this issue. We expect Amey Lafarge to fix this soon and at their own expense.

"We are very disappointed that this hasn’t been resolved by now, despite our persistence."

"We want to make residents aware of this potential issue so that if you spot that a light hasn’t turned on for one night, you’ll know why. I apologise for any inconvenience or concern this may cause." 

However the ongoing problems were criticised by opposition politicians in Watford, who said the issue should have been resolved in the three years since it first emerged.

Nigel Bell, a Labour county councillor for the Vicarage and Holywell area, said: "They surely should have had the changeover fixed by now after the-years since the policy of ‘part-night’ lighting.

"Why should Watford residents and all those potentially around the county have to go through power cuts in certain areas where the lights don’t come on at all at 6 or 7pm let alone from midnight to 6am, when of course we and many residents across Watford and the county don’t want them to go off at all."