Southend’s council boss has said plans for a £500m regeneration scheme may in fact change after it was revealed the Queensway underpass could be filled in and turned into a water tank.

When Southend Council launched a public consultation into the Queensway regeneration scheme, plans showed that the busy dual carriageway underpass would be scrapped, prompting accusations that councillors had been kept in the dark about the changes.

The Southend Conservatives - who, documents have since revealed, actually signed off the plan - have now published an open letter urging the Labour-led administration to ditch the plan.

They warn it will “reduce traffic flow through what is the only main artery in the centre of Southend”.

The letter adds the move would mean “continuous congestion” and would “reduce access to the east side of Southend and the seafront, but most significantly for the residents of Queensway, place a four-lane congested highway through the heart of their residential development”.

Labour council leader, Ian Gilbert, responded to the letter by reassuring his rivals that the design from the council’s development partner Swan Housing could eventually change.

He said: “The administration is not firmly committed to the proposed layout.

“We have discussed other options with the partnership, which are being actively investigated. There has been some good engagement work from the partnership, and we are taking seriously all points of view.

“I’m not going to make any promises or float any alternative proposals publicly until they have been subject to greater investigation, but I can assure people that all views are being genuinely listened to, and I will do my best to make sure that councillors get meaningful input rather than just a take-it-or-leave-it vote at the end.”

Currently, the dual carriageway underpass allows traffic to flow to the seafront without using the Porters roundabout. If it is removed all traffic to and from Victoria Gateway will have to negotiate two light-controlled pedestrian crossings and merge on to the Porters Grange roundabout.

After the plans were revealed, the Local Democracy Reporting Service obtained confidential documents from a February cabinet meeting which showed the Tories in fact agreed to the filling in of the underpass.

But Mr Gilbert said that when the scheme was agreed by the Tories former Conservative Councillor James Courtenay, who oversaw the project at the time, was “quite clear” about what was being agreed.

He said: “It could be changed, and still can be, but any changes are likely to involve trade-offs and compromise on different aspects.”