Medway Tunnel: £10.5m Bid to Replace Its 1996 Systems

Medway Council has asked the government for £9.25 million to rip out and replace the machinery that keeps the Medway Tunnel running. It confirmed the bid on Tuesday 25 August.

The money would come from the Department for Transport’s Structures Fund. The council says it would put in £1 million of its own, making a programme worth £10.5 million.

The tunnel is 30 years old this year, and most of what is inside it is not.

What the money would buy

The council’s announcement lists the renewal of the electrical, ventilation, pumping and life-safety systems. Its Medway Tunnel improvement programme page sets out the same programme as:

• the tunnel’s electrical distribution equipment
• ventilation systems
• safety essential operational infrastructure

The stated aim is blunt. The improvements are “intended to maintain the safe, reliable and resilient operation of the tunnel to avoid future unplanned closures”.

Why now

The structure itself is not the problem. The council says it “remains sound”. The systems threaded through it are the problem, because a good many of them still date from 1996.

In the council’s own words, “some system components have become obsolete, specialist parts are increasingly difficult to source, and what was once routine maintenance is now becoming increasingly complex and costly”. It puts the tunnel in the same bracket as other 1990s infrastructure where “the challenge is now major lifecycle renewal rather than one of ongoing routine maintenance”.

Cllr Alex Paterson, the portfolio holder covering highways, said the tunnel “presents a unique set of challenges with complex systems required to keep it operational” and that “the time has come where substantial investment is required”.

Cllr Simon Curry, portfolio holder for climate change and strategic regeneration and chair of Transport for the South East, made the funding point directly. “There are only a handful of specialist highway tunnel assets operated by a local authority across the whole of England,” he said, “meaning the Medway Tunnel presents unique funding and asset pressures for the council.”

Lauren Edwards, MP for Rochester and Strood, said she “strongly supports” the bid, and pointed at the tunnel’s role in connecting emergency services to the Hoo Peninsula and the Isle of Grain.

The scale of what is being kept going

The council’s figures for the tunnel:

• 720 metres long, of which the immersed section under the river is 370 metres
• more than 50,000 journeys through it every day
• three concrete tube sections, each weighing around 30,000 tonnes, around 90,000 tonnes in total
• built for £80 million and opened by the Princess Royal on 12 June 1996
• the first immersed tube road tunnel built in England, and the second of its type in the UK, after Conwy in North Wales

The three sections were cast in a basin dug out of the bank, sealed with bulkheads, floated out like submarines and sunk into a dredged trench. The council’s history of the build records that the basin took 600,000 tonnes of excavation and was flooded with 50 million gallons of water to float the sections out.

How £9.25m compares with what Medway normally gets

This is the part the announcement does not spell out. The bid is worth more than the council’s entire annual roads capital allocation from the Department for Transport.

Medway’s highways maintenance transparency report shows the DfT allocated £5,024,000 of capital for 2025 to 2026. That is the money for the whole network: 845km of road, 1,045km of footway, over 27,000 streetlights and 406 structures such as bridges and retaining walls. The tunnel is one of those 406.

The council also carries a mixed report card on roads. The Department for Transport’s local road maintenance ratings for 2025 to 2026 score Medway Amber overall, Amber for condition, Amber for spend and Red for wider best practice. Across England, 16 authorities were rated green, 125 amber and 13 red. Neighbouring Kent County Council scored Amber overall with a Green for spend.

The competition for the money

The Structures Fund is not a Medway pot. It opened on 15 April 2026 and sits inside a £1 billion package for England’s roads. Every local highway authority in England can bid, plus Transport for London. Eligible structures include bridges, flyovers, tunnels, culverts and retaining walls.

The key dates from the Department for Transport:

• draft applications were encouraged by 19 June 2026
• final applications closed on 3 August 2026
• funding decisions will be announced in autumn 2026
• successful schemes must finish their works by March 2030

Medway Council’s own page is careful about where things stand: “Our application is currently under consideration, and a funding decision has not been made.”

What it means for you

Nothing changes on your journey this week. If the bid succeeds, the work would have to be delivered before March 2030, and that would mean closures.

The tunnel already shuts for maintenance on a fixed rhythm. The council says closures happen every three months for three nights, with restrictions from 8pm to 6am, usually early in March, June, September and December, though the dates can move. Advance signs go up on the approach roads including the A289, and on motorway variable message signs.

The next quarterly closure is due early in September. The council had not published the specific dates on its own tunnel or roadworks pages when we checked on 26 August, and directs drivers to its roadworks map and to the signs on the approach roads. We will carry the dates on our Medway roadworks and travel page as soon as they appear.

If the bid fails, the council is back to maintaining 1996 equipment with parts it says are increasingly hard to find. That is the risk Cllr Paterson was describing.

More Medway travel and council coverage: roadworks and travel, parking in Medway, planning applications.