The Enquirer understands that suppliers and subcontractors were given the bad news by main contractor SCS JV on Friday.

Two giant tunnelling machines have been assembled and are ready to dig the HS2 tunnel between Old Oak Common and London Euston after Chancellor Rachel Reeves confirmed funding for the project in last year’s budget.

TBM drives are hoped to start within the next 12 months and take around 18 months to reach Euston.

But shaft and headhouse sites at Adelaide Road and Canterbury Works will remain on pause over the next two years while parts of the Euston drive including the station cavern, crossover tunnels, portal and scissor box are being rescheduled.

One subcontractor said: “You can imagine how that went down with the supply chain but nothing surprises me on this project anymore.

“A lot of firms will be hit for six by this because they have geared-up for the scheduled work.”

Suppliers were told the money saved from suspending the central London work would be diverted to the route from Birmingham’s new Curzon Street Station.

A source said: “The focus amid budget cuts now seems to be on the Curzon Street to Old Oak Common part of the route.”

HS2’s London tunnels contractor, Skanksa Costain STRABAG (SCS) joint venture will lead eventual construction of the twin-bored tunnel into Euston.

A spokesperson for HS2 said: “When HS2 opens, services will initially run between Birmingham and Old Oak Common in west London and this section of the railway remains the focus of our delivery.

“Last autumn, the government confirmed that HS2 will be built to Euston and we are now preparing for construction of the tunnel from Old Oak Common. Construction on associated works including the tunnel shafts, headhouses and station approaches will start at a later date.

“We are currently reviewing the whole HS2 programme as part of a major reset – making sure the building blocks of the scheme are in the correct sequence.”