The cost of a multi-million-pound tunnel project connecting 6.000 homes to Kent's biggest shopping centre has doubled in cost since plans were introduced.

Originally, in 2018, the Bean tunnel works near Bluewater were estimated to cost £13million and would link the Greenhithe site to the Ebbsfleet Garden City development.

Plans were approved in May 2020, despite some concerns about the safety of the 80-metre route, but had to be resubmitted last month after the time period to start work expired.

Now, Kent County Council (KCC) has confirmed the new cost of the project has almost doubled to £25.5m.

A spokesman said: “The revised budget for Bean Road Tunnel is £25.5M with a construction cost estimate of £20.5M.”

If approved for a second time, the tunnel will connect 6,000 homes from Ebbsfleet Garden City’s Eastern Quarry, known as Whitecliffe, to Bluewater.

The council attributed the rise in costs to a combination of the Covid-19 pandemic and “unforeseen increases in the price of materials”, compounded by the war in Ukraine, inflation and rising interest rates.

According to KCC, the main construction works are currently being reviewed in light of the “updated cost estimates and funding available to deliver the scheme”.

Additional funding has been made available through the Bus Service Improvement Plan (BSIP) tranche 2 from the Department for Transport (DfT) which has enabled the scheme to move forward with a potential start of construction in spring 2025.

Documents for the resubmitted plans were first sent to the county council before the end of July.

Four years ago, planning bosses unanimously backed the plans which would be accessible for buses, cyclists and pedestrians.

The applicant says it will relieve “unacceptable traffic congestion” in the area and benefit thousands of future homeowners. Plans were also backed by Dartford council.

There were some concerns at the time, including from Maidstone county councillor Ian Chittenden (Lib Dem) who said there were “serious questions” about the safety of people using the tunnel.

He said: "There is a risk that buses could lose control being so close together with cyclists and walkers.”

His comments came after the Bean Residents' Association expressed fears over the safety of pedestrians and cyclists sharing the tunnel with buses, while councillors worried of "vandalism" to entrances.

To see more planning applications and other public notices for your area, click here.

Critics complained the plan is "essentially an enhanced bus route" and other anxieties have been expressed over safeguarding the site for any future use as a tramline, following the examples of Croydon and Manchester.

KCC planning officer Paul Hopkins said the "underpass" would only take 18 seconds for cyclists to travel through and 60 seconds for pedestrians.

He added it is "sufficient size" for the operation of any future tram service.

Buses will use the site every five minutes, travelling at slow speeds of 20mph, while these will be electric vehicles to boost their climate change strategy.

In July this year, £200m plans to rip up cark parking spaces and regenerate land around Ebbsfleet International to create a new “civic heart” for the garden city project were approved.

The development, known as Ebbsfleet Central East, will see the brownfield lane repurposed to create a new city-style centre.

Parking facilities will be relocated as a multi-storey structure nearby and the land transformed into a new business quarter, thousands of new homes, and fitness and wellbeing facilities.

It forms part of overarching plans being driven forward by Ebbsfleet Development Corporation (EDC) - the planning arm tasked with delivering the scheme for a “21st century garden city” with up to 15,000 new homes - and is backed by the government.

The plans are supported by an illustrative masterplan which includes 2,100 homes on the Central East site, of which 35% are designated as affordable housing, alongside 87,000 sqm of office space, retail and leisure facilities, new open spaces and connectivity improvements.

The outline planning application commits to the delivery of a GP healthcare facility and EDC says it will continue to work closely with NHS partners to deliver this as part of a world class “health and wellbeing hub”.

These facilities, together with space for business, education and research, will make up a health, education and innovation quarter.

Other potential uses on the site allow for co-living and student accommodation, public houses and drinking establishments, and theatres and cinemas.

According to documents submitted alongside the proposals, nearly £8 million could also be set aside for a contribution towards a new secondary school site, as well as a new facility for children with special educational needs.