Taxpayers will be stuck with millions of pounds of costs when a council deal to buy the Medway Tunnel for £1 is finalised, a government minister has said.

Jonathan Shaw (Lab), MP for Chatham and Aylesford, has attacked the deal by the Rochester Bridge Trust (RBT) to transfer its ownership of the tunnel to Medway Council.

If the transfer, which was approved by council chiefs in May, is completed, the RBT, an organisation thought to own assets worth £70 million, would shift the entire cost of upkeep to the council. This could be as much as £2 million a year.

Since 1998 Medway Council has had a responsibility to maintain the tunnel, but the RBT has made contributions to the upkeep. These contributions would cease after the deal.

Mr Shaw, who is also the minister for the South East, said: "This bad deal will burden Medway residents with a £2 million bill every year.

"This bad deal could lead to a cut in services or higher council tax bills."

Mr Shaw has also criticised the accountability of the deal because council leader Rodney Chambers is the senior warden of the RBT, and has had to be excluded from council discussions about the purchase.

He is calling not only for the cost of the tunnel to be transferred to Medway Council, but the full assets of the RBT as well.

He said: "I have serious concerns the leader of the council and chief warden of the RBT are the same person.

"I call for a halt to any agreement being finalised and the assets and responsibilities to be transferred to the local council and elected officials to stand up for the people of Medway."

Medway Council agreed it would buy the tunnel in May.

The offer was the subject of detailed negotiations with the RBT, which was refusing to pay the full cost of maintenance.

If the deal is finalised, it will leave council taxpayers with the responsibility for one of the most criticised tunnels in Europe.

The tunnel has been criticised by safety experts as being past its sell-by date and controlled by an antiquated computer system.

It cost the RBT £160 million to build in the early Nineties.