London Underground could take over construction of the Croxley Rail Link and the projected cost will rise to £230 million.

Hertfordshire County Council and the rail provider are discussion about who will be responsible for specific aspects of the project, but it has emerged London Underground could take over the construction of the project later this year.

The county council attributed the higher price of the project to 'wider railway benefits' and the cost of inflation. The scheme had been expected to cost in the region of £120 million.

Jo Brown, from Hertfordshire County Council, said: "The wider railway benefits include refurbishing the existing line between Lower High Street and Watford Junction, as well as enhancing the power supplies to both the Metropolitan Line and the Network Rail sections.

"The improvements being made will allow more trains to run in the future, not just on the Croxley Rail Link but on the wider train network.  

"In addition, while the Croxley Rail Link will not immediately enable services to run from Amersham into Watford Junction, it has been designed so that this can happen in the future with minimal work."

Construction has also been put back until Spring after it had been scheduled to start earlier this year. 

Dorothy Thornhill, Watford’s Elected Mayor, described the rail link as "absolutely critical to unlocking Watford’s future economic potential".

The Liberal Democrat prospective parliamentary candidate said: "The Croxley Rail Link is a transformational project for the town.

"It is the thread that links Watford’s major development projects together - Watford Health Campus, Ascot Road, Watford Business Park, Watford Junction Interchange and Charter Place Shopping Centre. 

"That’s over £1.2 billion of investment to the benefit of our residents and businesses." 

The scheme will see the Metropolitan Line routed from Croxley Station, to a new one in Ascot Road called Cassiobridge, then another new station in Vicarage Road called Watford Vicarage Road before connecting with Watford High Street Station and then terminating at Watford Junction.

As a result of the scheme Watford Metropolitan Station will close to passengers and be used as siding.

David Hughes, London Underground’s Director of Major Programme Sponsorship, said: "We are supporting Hertfordshire County Council with their proposal to re-route and extend the Metropolitan line to Watford Junction. 

"The Croxley Rail Link will improve access to public transport for local residents, lead to jobs growth in the area and provide access for Metropolitan line passengers to West Coast mainline National Rail links from Watford Junction station."