The future of a subsidised ferry service is in doubt due to potential funding issues.

The crossings, between Gravesend and Tilbury, which provide 100,000 journeys each year, have been kept afloat for more than 20 years with grants from Kent County Council (KCC) and Thurrock Council.

Passenger revenue alone is insufficient to cover the costs of the boat crossings.

But Thurrock has been placed in special measures and KCC is facing a massive spending squeeze, causing major concerns over continued funding.

KCC will start a consultation in January into how the service is being used and the impact should the service stop running beyond the current deal which expires in March 2024.

The current contract provides sailing for foot passengers every half an hour between 5.40am and 7pm on Mondays to Saturdays from Gravesend Town Pier.

During recent negotiations around a contract extension with the operator, the Essex local authority advised KCC it has concerns about its ability to continue the subsidy long-term.

The subsidy is currently funded exclusively by KCC at an annual rate of £55,000 but without further external money, Kent would have to allocate nearly four times that amount to keep the service going beyond March 2024 when the cost would rise significantly.

A return fare currently costs £5.50 and ten journey pass £25, according to Thurrock Council.

A KCC statement said: "Due to the financial pressures KCC is facing, it is unclear whether KCC could commit to funding the service in its entirety moving forward and the funding that the council has historically made available would not be enough on its own to sustain the service.

"This means that there is uncertainty about the future of the service beyond the end of the current contract which expires at the end of March 2024.

"The council will therefore be running a public consultation to understand how the service is used and what the impacts would be if it were to stop running."

KCC’s cabinet member for highways and transport, Neil Baker, said: “We understand the important role this ferry service has in serving both Gravesend and Tilbury.

“As KCC is now the sole authority subsidising this service, we have a responsibility to the Kent council taxpayer to ensure we are spending money wisely.

“I am keen to get people’s views on this service, which is why I’ve instructed my team to launch a public consultation to help inform any decisions that are made in future.”

Cllr Baker said regular users of the service are currently Kent residents who work at Tilbury docks and Essex children who commute to Kent for schools.

He added that there are "no foregone conclusions" regarding the consultation but sees it as a "deep dive" into the way the service is currently used.

KCC, like many English local authorities, has to find tens of millions of pounds of savings next year in order to avoid issuing a Section 114 notice, which would effectively mean it is bankrupt.

The authority's leadership has pledged to find discretionary savings in order to protect its statutory obligations, such as adult social care and the care of unaccompanied asylum seeking children.

Thames Clippers, which took ownership of Gravesend Town Pier last year, plans to run its Uber Boats' service into London from Kent.

The company bought the historic landmark from Gravesham Borough Council late last year so the authority could redirect running and maintenance costs into essential services to residents.

Thames Clippers consulted with Kent County Council during the purchase and vowed to continue to support other operators "whoever they might be" as well as accommodate visiting vessels, although its own craft would need permanent access.

The firm's acquisition of the pier is not thought to have a bearing on the councils' position on subsidies.

A ferry crossing has existed between the two towns for hundreds of years, even as far back as Roman times.

It once carried cars but that service ended with the opening of the Dartford Crossings.

Jetstream Tours, which runs the Gravesend to Tilbury passenger service and other popular pleasure boat trips, was approached for a comment.