Highways teams have begun testing the new traffic lights by the Medway Tunnel – seven months after they were installed and more than three weeks later than planned.

The lights have been on green since they were set up in March but yesterday afternoon they turned red for the first time just before rush hour.

The trials will continue for several weeks on different days and the council will be monitoring the impact on surrounding roads.

It is good news for the 5,000-plus workers on the Medway City Estate, who have been plagued by daily delays for years.

There have been calls for controls help people get off the estate and reduce queues at peak times.

But the council would not agree to lights on the Medway City Estate roundabout, by McDonald’s, because they did not want cars queuing in the tunnel.

In 2014, it seemed that workers’ pleas had finally been answered when the council agreed to put traffic lights on the Gillingham side of the tunnel, which were eventually installed by the slip road to Chatham in March.

A council spokesman said: "This was the start of a testing period that will span several weeks during which we’ll be monitoring traffic flow while trying out various light sequences.

"We are hopeful the lights will play an important role as part of a wider scheme to alleviate congestion at peak times in the evening for those leaving the Medway City Estate, while maintaining a steady traffic flow in the surrounding areas.”

The lights are designed to briefly hold traffic, creating a gap on the Strood side so motorists can leave the estate more easily.

The idea followed a scheme introduced by Medway Council when traffic was made worse because of roadworks in Strood.

Slow moving Highways lorries were sent through the tunnel on a loop to slow the traffic down behind it. The Medway Messenger observed the lorries in action and a 20-second break in the traffic allowed around 100 cars off the business park.

The lights have been delayed because it was decided speed cameras were needed to make sure motorists did not speed through the empty tunnel when the lights turned green. The 50mph average speed check cameras were installed in June.