The possibility of a sinkhole in Hertfordshire has forced the closure of a road while "vital" repair works are carried out, a council has announced.
The region's county council revealed that preliminary investigations on a hole in St John's Road, Watford, were put on hold over worries of further erosion and weakening to the road and footpath.
A council spokesman said access to the commuter road could be blocked for up to four days, with drivers advised toplan an alternative route in advance.
He added: "A geotechnical engineer present during the investigations advised that there is a possibility that a sinkhole exists deep down in the underlying chalk.
"It is possible that by exposing the hole and then subsequently back-filling, this will cure the problem. If this is the case, the road is likely to be closed for up to four days. A small section will be resurfaced upon completion."
Terry Douris, the council's cabinet member for highways, said: "I am aware of the importance of this road and we apologise for any inconvenience that these urgent works may cause residents and road users.
"It is vital that this work is carried out without delay to ensure everyone's safety. We will do our very best to keep disruption to a minimum, but we are aware of the impact that these roadworks will inevitably have."
Copyright Press Association 2014