A stretch of the A1 near Newcastle and Gateshead will not reopen until Wednesday (29 June) after a 6.5 metre sinkhole opened under the carriageway.
The hole is at least 3m deep and around 6.5m diameter and is believed to be related to old mine workings in the area.
It means the A1 northbound is currently closed between junctions 67 (Coal House) and 68 (Lobley Hill) on the western side of Newcastle and Gateshead.
Highways England say work has been ongoing to investigate the extent of the hole, and start the necessary repair to make the carriageway safe for traffic. As that work continues extra measures are being put in place to minimise disruption; this includes introducing a contraflow on the southbound carriageway, lifting toll barriers for the Tyne Tunnel, and suspending roadworks on other key routes which are likely to be affected by traffic diverted from the A1.
Rob Beckitt, duty operations manager at Highways England said: “Safety is our top priority; we have to ensure the carriageway is totally safe before drivers use it.
“We and our contractors have been working hard with partners since the hole was discovered last night, and will continue to do so to make the carriageway safe as quickly as possible. In the meantime I urge all drivers in the area to check conditions before they set out and to leave plenty of extra time for their journeys. I would also like to thank drivers in advance for their patience as we carry out this complex task.”
The large hole under the A1 was discovered by Highways England on Saturday night when a slight dip in the road surface became apparent. Workers then cut around the dip to investigate and discovered a large void underneath the road surface. It was in a coned off stretch due to roadworks elsewhere on the A1, so there was no traffic using the road at the time.
The hole, estimated at around 140 cubic metres, is being filled with a specialist concrete mixture before the road is resurfaced. Following that contractors working for Highways England will need to drill holes on Tuesday to pump more material underneath the repair to prevent a repeat collapse. If all goes to plan they are hoping the road will be safe to re-open on Wednesday morning.