The cause of the flooding that closed Gdynia Way in Plymouth two days running this week has been found and removed.
Engineers from South West Water dropped CCTV cameras into the sewer beneath the major Plymouth road after it was closed for seven hours on Wednesday then three hours on Thursday.
The closure caused major disruption across the city with traffic tailbacks spreading through connected roads.
Even after the floodwater drained a significant amount of debris was left on the road, meaning it had to stay closed.
Now engineers have found a lump of concrete and rubble the size of a kitchen sink which was stopping water from draining at Barbican Approach.
The lump was found in a sewer near Barbican Approach, close to the Vue cinema on the Barbican Leisure Park.
Barbican Approach leads on to Gdynia Way, which was widened as part of the roadworks which started in 2010.
A South West Water engineer had to climb into a manhole about 60cm across to tie a rope around the lump so that it could be pulled free.
A spokeswoman for the water company said the blockage was in a 75cm diameter sewer.
“It could not have come from Gdynia Way because the sewers there are only 25cm diameter,” she said. “It must have originated in the leisure park.
“But we are not resting on our laurels. We’re keeping a close eye on the sewers.
“Fingers crossed, that was the culprit.”
South West Water started the search for the blockage yesterday, sending CCTV cameras into the sewer system to survey the network around Gdynia Way.
“There is no way of knowing for certain how the concrete came to be in the sewer or how long it has been there,” the spokeswoman said.
“It measured about 40cm across by 25cm wide (almost as big as a kitchen sink) and appears to consist of hardened mortar and rubble.”
A spokesman said: "There is no way of knowing for certain how the concrete came to be in the sewer or how long it has been there."
The flooding came just months after Gdynia Way underwent extensive roadworks as part of a £19million package.
There were fears the sewer had collapsed, which could have meant more roadworks and road closures.