Engineering work to upgrade gas mains in Gravesend is expected to last until mid-March.

More than 600m of old, metal pipe in Milton Road is being replaced with plastic.

It appeared to have started without warning as a stretch of Milton Road on the one-way system between the junctions with Queen Street and West Crescent Road was initially coned off, allowing two lanes of traffic to filter into one.

However, traffic flow is now also being controlled by temporary lights at the top of Harmer Street.

The work is being carried out by gas distribution company SGN. Spokesman Chris Jacobs said it was essential in order to ensure “a continued safe and reliable gas supply” for local homes and businesses.

He added that engineers were working extended hours and also on site on Saturdays. Minor delays have been caused, with vehicles tailing back on occasions as far as St John’s Secondary School in Rochester Road during the morning rush-hour.

“We understand that roadworks can be frustrating,” said Mr Jacobs. “For everyone’s safety while we upgrade the network it has been necessary to put in temporary traffic lights.

“We are working closely with Kent County Council and doing everything we can to reduce disruption.”