A project aimed at reducing traffic will actually make journey times longer.

The third phase of the Valley Gardens project in Brighton will replace the Palace Pier roundabout with a junction in a bid to make the road safer.

But a Brighton and Hove City Council report obtained by a Freedom of Information request shows the new scheme will extend journey times for drivers.

On average, commuters will spend an extra 27 seconds in their cars every day if the scheme goes ahead.

And those driving home at rush hour in the afternoon will take an extra 55 seconds.

The delays are expected to cost the economy £1.2 million each year according to the report.

Conservative city councillor Lee Wares said the scheme would bring “economic disaster” to Brighton if it went ahead.

“The true cost of the transport disbenefits could be significantly higher in reality than what the business case shows,” he said.

“This project shows no benefits in respect to its costs.

“And it will only get worse when the Dukes Mound junction is modified because that will introduce another stop-start point on the A259.”

A council spokesman said it was confident things had moved in a more positive direction since the report was published.

“The scheme will rebalance the environment and calm traffic passing through the city, bringing many improvements that outweigh some minor journey time delay on the A259,” he said.

“This is due to the need to control and make the Palace Pier junction safer.

“Any disadvantages are outweighed by the benefits that we will see in terms of collision reduction and sustainability benefits including more cycling, walking and public transport usage.”

The spokesman also downplayed the £1.2 million annual economic loss, arguing some A259 commuters are not directly linked to Brighton’s economy.

“The figure is not a cost to the council, nor is it linked to the city or local economy,” he said.

“Many motorists driving through the city, particularly on the A259, are passing through and as such are not directly linked to the local economy.

“In terms of calculating the overall costs and benefits to the city, this is just one of a wide variety of statistics in play.”

The city centre project received a boost in October when the Coast to Capital Local Enterprise Partnership agreed £6 million in funding for the scheme.

If the plans go ahead, the city council will also create new public spaces in front of Pavilion Gardens and the Royal Albion Hotel.