A section of a divisive 'magic roundabout' with 36 sets of traffic lights has been cordoned off after a sinkhole suddenly opened up. 

The main route into Cambridge's city centre was closed in both directions between Mitchams Corner and the Elizabeth Way roundabout on Monday afternoon. 

Local police were deployed to the scene to manage traffic at about 3pm. 

Highway teams are still investigating what triggered the sinkhole, which can be caused by sewer collapses or extended dry spells that dissolve soluble bedrock. 

City Councillor Delowar Hossain said the sinkhole, which is estimated to be two to three metres deep, raised questions about the quality of the road works.

'The entire road now needs a full investigation from top to bottom to ensure safety and prevent a serious accident in the future,' he said. 

Elisa Meschini, a councillor and former chair of the Greater Cambridge Partnership, questioned if Anglian Water works could have caused the sinkhole. 

'If Anglian Water have caused this, the taxpayer should not foot the bill,' she said.

The company said it had attended the site but did not believe the works were connected to the incident, according to The Times.

Cambridge City Council on Monday said the road will be repaired as quickly as possible and reopened when it is safe to do so. 

The sinkhole has renewed fierce debate over the CYCLOPS (Cycling Optimised Protected Signals) junction which first opened in October 2024. 

The work on Milton Road was part of a £24million overhaul by the Greater Cambridge Partnership to improve walking, cycling and public transport routes.

However, the 'signalised' roundabout has angered residents, with drivers complaining of long queues forming when they are held at red lights.

The new CYCLOPS junctions feature a protected cycle lane which encircles the junction, keeping cyclists separate from both motor traffic and pedestrians.

People cycling can make a signal-free left turn at any point or use the dedicated cycle buttons to access the green phase of traffic signals, allowing them to make a right turn or travel straight on without having to mix with vehicles.

Pedestrians cross at the same time as cyclists, but on a separate ring of paths in the middle of the junction, whilst zebra crossings on each side provide a safe place to cross the cycle lane. 

But residents say the large number of traffic lights are a 'total waste of money' and make existing traffic jams even worse. 

Just days after the new junction opened, locals went online to vent their frustrations. 

One person said on Reddit: 'Originally I thought the lights would be only for pedestrians when they want to cross but no, these lights are on all the time!'

They added: 'I travelled through there twice in off peak hours and each time there was a long queue of cars standing on idle because the red light is there for an incredible long time while there is zero traffic on the roundabout itself.

'Besides, don't traffic lights defeat the purpose of a roundabout?'

It comes after the council released a YouTube video tutorial explaining how to use another CYCLOPS junction after drivers struggled to navigate it five years on.

The junction where Histon Road meets Gilbert Road has four zebra crossings, four pedestrian islands and eight sets of traffic lights.

The city's Conservative group has blasted the Cyclops format for 'causing chaos for cyclists, pedestrians and drivers alike' and potentially leading to 'extra confusion'.

They also pointed to an 'increase in collisions', with data showing six 'slight injury' crashes in the three years since 2021 compared to one serious injury and four slight injuries between 2016 and 2019.

Greater Manchester was the first UK region to implement Cyclops junctions, with the initial one opening in Hulme in July 2020, before a second in Bolton in January 2021.

Others have followed in Bury, Preston, St Helens, Trafford and Bradford - with more being built in Rochdale and Salford as well as proposals in Hull and Windsor.

Cambridge City Council has been contacted for further comment.