The Abbey Flyer railway line, which links Watford Junction with St Albans Abbey, is to be converted into a tram system, the Secretary of State for Transport Andrew Adonis confirmed this morning.

Mr Adonis, speaking at Watford Junction, said the new scheme will offer a more frequent service of up-to three trams an hour, rather than the one every 45 minutes currently offered.

The increased service will be made possible by the building of a passing loop on the line, allowing two trams to operate at any one time along what, at present, is a single track route catering for some 450,000 passengers each year.

Dependent on the outcome of a 12-week public consultation, ownership of the line will be transferred from Network Rail to Hertfordshire County Council, which will then tender for a contractor to run the service.

Mr Adonis did not say precisely, however, what timetable would be offered but said “in principle” the service could run later into the night, allowing greater access to both towns’ night-time economies.

He told the Watford Observer: “This project would make it possible to run later trains but it would be up to the county council to decide what the service pattern is. But, in principle, it would be possible to run later.”

Asked why his department had singled out Watford for such attention Mr Adonis, a well-known railway enthusiast, replied: “Because a very exciting proposal was put to me by the county council and I am keen to respond to innovative local projects like this one.

“Local people want to see a more regular service and this will make it possible. It will be a very significant enhancement to the area. It will reduce rail congestion and is a real win-win.”

Hertfordshire County Council said the project could be up-and-running by the end of 2011 and insisted disruption to commuters’ journeys during any construction work would be minimal.

Funding for the project, an amount yet to be announced, will come directly from the Department for Transport, which will simply transfer the existing subsidy it currently pays London Midland to operate the service to the project.

Watford MP Claire Ward said: “I welcome this good news for the community.

“The Abbey Flyer is going to be put on a firmer footing and there will be better services.

“It is good news, both for Watford and for people who commute from St Albans to London.”