THAMES Water says the repairs it is carrying out to a leaking water pipe in Notting Hill Gate are among the most complex they have ever done.

Work started in early April, but when engineers dug down to expose the 30-inch main, they discovered the ground underneath it had disappeared causing huge voids under the busy road.

To protect the safety of drivers, the road was closed on May 1 and remains closed while investigations continue to find out how the voids appeared.

From this week the road closure will extend to Pembridge Gardens. This is to allow a temporary pipe to be installed while the leaking one is repaired. Pembridge Gardens will still be accessible from Pembridge Square.

Mark Taylor, Thames Water’s North London project manager, said: “This has been one of the most complex jobs we have ever done. The extent of the voids has gone far beyond what we expected. Until we know where the soil has disappeared to, we don’t want to just pour in a load of concrete because the chances are, that will disappear too.

"We’re working on a process of elimination but we believe we will get to end of this problem in the next few days. Once we have done that, we can then make the road safe and start repairing the water pipe."

As well as having to deal with the voids in the road, Thames Water will also have to work with National Grid to move a 24-inch gas pipe which runs over the top of the water main.

Mr Taylor added: “We need to ensure the ground is stable before we bring in the crane to move the gas pipe. Then and only then can we actually get to work on our water pipe. Once this happens, we expect the work to take around four weeks – but as we have already learned on this project, that could get delayed if we face any more unexpected challenges.”

A spokesman for the Royal Borough of Kensington and Chelsea, said: “The Council appreciates how disruptive these works are and is continuing to work closely with Thames Water to ensure they are completed as quickly as possible. We have arranged for other works to take place while the road is closed to avoid future disruption.”

For updates on the closure from Thames Water, subscribe to the ‘Text for Updates’ service by texting ‘Notting’ to 80007.