Midlands Metro's £137m extension delayed by HS2

An artist's impression of the proposed Curzon Street Station transport hub

A £137m extension to West Midlands Metro has been delayed by HS2.

The Eastside Metro line would reach to the Digbeth area of Birmingham, passing underneath Curzon Street Station - a yet-to-be-built hub for the proposed high speed rail network.

But the tramline extension, initially earmarked for a 2022 opening, is still waiting for Government approval amid uncertainty surrounding £56bn HS2.

HS2 says it is working to ensure Eastside's "successful integration".

The extended tramline - set to offer connections with Birmingham railway stations New Street, Moor Street and Snow Hill - may not be operational until 2026, the BBC understands.

Documents seen by the BBC reveal HS2 is concerned that planned construction at the Curzon site presents "logistical challenges".

An HS2 spokesman said the project was working closely with Metro owner-operator Transport for West Midlands (TfWM) to ensure the successful integration of the Eastside extension - a "vital part of the connectivity to the new high speed rail network".

He added: "Taking more time now will help us deliver contracts which, in the long term, deliver best value for HS2, the taxpayer and our future contractor."

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An artist's impression of the Eastside Metro line in Digbeth

Analysis by Peter Plisner, BBC Midlands Business and Transport Correspondent

Building tram lines in city centres is never easy, but add in the fact that the Birmingham Eastside extension has to cross a worksite occupied by HS2 and things inevitably become even more complex.

With the funding in place, TfWM just needs approval and powers to build from the government. But obtaining the powers has been more difficult than anyone envisaged.

Ministers had clearly been holding back from giving the green light to the scheme while negotiations between HS2 and TfWM continued.

It means that a deadline to have the scheme up and running in time for the Commonwealth games has now been missed and instead the line will be built in two halves and connected in the middle once HS2 has built its station.

It's far from satisfactory, but at least it gets the bulk of the line built.

Ian Ward, leader of Birmingham City council, said: "There's always going to be difficulties along the way and likely delays.

"We'll continue to work with HS2 to ensure we can link up the Metro line through to Digbeth and that side of the city as quickly as we can."

Laura Shoaf, managing director of TfWM, said the original plan was to have the extension completed by 2022.

"We've been unable to achieve that in part because of the delay in the build of [Curzon Street] station itself," she said.

"What we're trying now to do is to achieve the best result we can."