Mysterious sinkholes that suddenly appeared in Goldington Road caused alarm to residents over the bank holiday weekend.
The first hole, which was near the junction with Merton Road, was six feet wide.
It was so large that one clever resident stuck a To Let sign in it to warn unwary motorists.
The council promptly filled the hole – but in doing it appeared to open up another one,
This one is about three feet deep, say residents.
A council spokesman told the T&C: “The council closed this road while works were carried out in conjunction with Anglian Water.
She added: “These works have since been completed and the road has now been reopened.”
A sinkhole is any hole in the ground that forms where water gathers without external drainage.
As the water is draining below the ground, it can dissolve concealed caverns under the surface.
This often happens in areas where the rock is made of water-soluble evaporate rocks such as salt or of carbonate rocks like limestone.
Sinkholes and potholes sometimes look the same, but there is a fundamental difference: potholes push upwards, while sinkholes cave inwards.
A pothole begins with a crack on the road’s surface, caused by factors such as the weather or a failure in the materials used.
Vehicles will then put stress on the crack, making it worse.