HS2 Ltd is the non-departmental public body responsible for delivering the HS2 programme. This includes responsibility for HS2’s Main Works Civils Construction, which in turn includes the construction of all tunnelling between Old Oak Common and Euston. Great British Railways will not assume this responsibility.

The Department and HS2 Ltd are currently undertaking a full reset of the HS2 programme, with revised cost and schedule ranges being developed. Once this work has been completed, these ranges will be published to Parliament.

From Old Oak Common station, the twin bore Euston tunnels will head north-east under Kensal Green Cemetery before broadly following the line of the Network Rail West Coast Main Line into Euston. The alignment curves in a southerly direction under Primrose Hill and the bored tunnels will end beneath the junction of Parkway and Gloucester Avenue.

From this point the twin bore tunnels will transition into a group of structures termed the Euston approaches, rather than interfacing directly with the station at Euston. The Euston approaches include a set of sprayed concrete lined (SCL) tunnels that connect to the twin bored tunnels. The Euston approaches will broadly cover the area between London Zoo car park and Hampstead Road.

The immediate structure that is to interface with Euston station is a retained cutting, which extends for circa 600m from a northerly direction to the entrance of Euston station. This will enable the HS2 lines to fan out into the necessary configuration for the station and its platforms.

The six major rail tunnel and road milestones completed ahead of schedule in 2025 are as follows:

Euston is key to realising HS2’s transformational growth benefits. Tunnelling to Euston from Old Oak Common is the most cost-effective approach, as the construction of Old Oak Common is set up for this purpose.

The Government has been collaborating with key partners to develop affordable, integrated plans for the Euston Station Campus, which will include the new HS2 station. We will set out more details in due course.

The Euston tunnels' scope is being delivered as part of the SCS Main Works Civils contract, and there are no plans for a new procurement process for this work. Due to commercial sensitivities, the department is unable to provide a specific cost breakdown for the Euston tunnels.

Previously published cost ranges for HS2 Phase One included the costs associated with the Euston tunnels. The Department is currently working with HS2 Ltd to review the Estimate at Completion (EAC) for HS2 Phase One. The results of this review, which include considerations of the Euston tunnels, will report to Parliament in due course.

The route and alignment of the HS2 tunnels from Old Oak Common to Euston are bound by the High Speed Rail (London – West Midlands) Act 2017. HS2 Ltd is responsible for designing and constructing the tunnels and grade separation and is continuing to progress with the current design ensuring compliance with all requisite technical, safety, and environmental standards. The design has been refined to minimise ground movement, and settlement mitigation measures have been developed to ensure compatibility with the operation of the existing railway.

The alignment remains materially unchanged and is publicly available on the HS2 website.

The alignment immediately approaching and within Euston Station will be subject to the finalisation of the station.

The Government has confirmed its committed to delivering HS2 between Birmingham and Euston at the recent budget. The scope of Phase 1 is being reviewed to ensure the HS2 scheme is delivered at the lowest reasonable cost, including the revised approach to Euston. Once this work has been done, we will publish to Parliament a revised cost range for the revised HS2 scheme including the cost of the tunnels from Old Oak Common to Euston.

HS2 Ltd is responsible for designing and building the Euston Approaches. The Company is continuing to progress with the existing design for the approach tunnels and grade separation in line with the requisite technical, safety and environmental standards at all times. The design of the HS2 tunnels has been refined to minimise ground movement and settlement mitigation measures have been developed to be compatible with the operation of the existing railway. As set out on the Network North Command Paper the HS2 station at Euston will comprise 6 platforms which can accommodate the trains we will run to Birmingham and onwards.

The exact design of the model to be used, how it is taken to market, as well as how and where the alternative funding generated by this will be spent, is commercially sensitive and still subject to further work to ensure we are optimising funding and delivery.

There will be a range of options within this that are still being considered and will require more time to develop before a final proposal is determined. Creating an alternative financing model that delivers value for money for the taxpayer will take time to develop.

The Government’s ambition remains to make best use of funding from alternative sources to enable delivery of the whole project and to ensure that funding is underpinned by contributions from those people and businesses this development supports. Options for using this alternative funding to cover the costs of the tunnel between Old Oak Common and Euston are also being considered.

Five tunnel boring machines (TBMs) have been launched to date. On HS2’s longest tunnel, the Chiltern Tunnel, both TBMs ‘Florence’ and ‘Cecilia’ have passed the Amersham vent shaft and are now more than 5-and-a-half miles into their 10 mile drive. In Warwickshire, HS2 completed the first tunnel bore under Long Itchington Wood in July 2022 and the TBM ‘Dorothy’ has been relaunched for the second tunnel bore. In West London, two TBMs ‘Sushila’ and ‘Caroline’ were launched in October 2022 from West Ruislip to create the first section of HS2 tunnel in London. The progress of TBMs can be tracked on the HS2 website.

In general, the height of the evacuation walkway in HS2 tunnels is 760mm above top of rail. For some specific locations due to track gradient and drainage constraints there is some small variability in this figure.

Analysis has been undertaken by HS2 Ltd for a number of different tunnel evacuation scenarios. The critical time is the period for passengers to evacuate the incident train, onto the tunnel evacuation walkway and pass through a cross passage to a place of relative safety in the other tunnel bore.

HS2 Ltd’s modelling estimates that:

• For a 200m long train carrying 550 passengers this is between 12 and 17 minutes depending on the location of the fire and the train stopping position.
• For a 400m long train carrying 1100 passenger this is between 14 and 24 minutes depending on the location of the fire and the train stopping position.

For passengers with mobility impairment, the design of any evacuation ramps or devices carried onboard the train are fit for use by all passengers. Evacuation wheelchairs will be carried onboard the train to aid passengers with mobility impairment where necessary. In addition, onboard staff would facilitate any evacuation as necessary.

HS2 Ltd has no plans to place copies of any reports relating to this subject in the Library of the House.

The HS2 route alignment has been designed to enable operation at speeds up to 360km/h on main route north of the northern portal of the Chiltern Tunnel where the topography and other constraints permit a suitable track alignment to be constructed. Between Euston and the Chiltern Tunnel north portal, the design speed progressively increases to a maximum of 320km/h.

There are no speed restrictions planned as a result of tunnel diameter or the piston effect of the train.

The HS2 infrastructure forming the approaches to Euston station consists of (from south to north): a portal structure leading to three sprayed concrete lined tunnels (two Up Line tunnels either side of a single Down Line tunnel). The two Up Lines converge into a sprayed concrete lined cavern and then merge into a single bored tunnel. The Down Line passes underneath one of the Up Line tunnels to merge into a bored tunnel adjacent to the cavern.

A sprayed concrete lined crosscut tunnel, perpendicular to the running tunnels is constructed from a shaft adjacent to Park Village East to facilitate construction of the cavern and provide a permanent intervention facility.

The Network Rail approach lines into Euston, including the Parkway Tunnels are located directly above the HS2 tunnels. Working in partnership with Network Rail, the Parkway Tunnels and Network Rail's railway tracks and systems have been the subject of Ground Movement Assessments by the HS2 Main Works Civils Contractor. The output of this assessment is currently being reviewed.

The design of the HS2 tunnels is being refined to minimise ground movement and settlement mitigation measures are being developed that will be compatible with the operation of the existing railway. The tunnelling is undertaken incrementally in small stages, which limits risk and means any settlement occurs in small stages allowing the existing railway infrastructure to be adjusted, as necessary.

The independent assessment of the Wendover mined tunnel proposal, and its terms of reference, are not intended for publication and are internal to the Department for Transport.

The slurry treatment plant at the Bromford East Portal is subject to an environmental permit application. This permit application sets out how potential impacts associated with noise, dust and vibration will be managed. Once approved, the implementation of this approach, together with the controls set out in the HS2 Code of Construction Practice, will ensure any impacts associated with the activities are appropriately controlled.

HS2 Ltd proposes to take forward the Bromford tunnel extension under powers provided by the High Speed Rail (London to West Midlands) Act 2017. HS2 Ltd has undertaken an environmental screening assessment which has concluded that there are no new or different significant adverse effects resulting from extending the tunnel, beyond those previously assessed in the Phase One Environmental Statement, which can be found online. By placing more of the route underground, there will be a reduction in environmental effects, including reduced impacts on ancient woodland, Park Hall Nature Reserve and the River Tame. There will also be fewer lorry movements. In order to resolve a potential legal inconsistency, HS2 Ltd has recently applied for a Transport and Works Act Order to remove three words from Schedule 1 of the Act.

The decision to promote an extended tunnel at Bromford, and the decision not to promote a bored tunnel at Wendover, were taken by HS2 Ltd, as scheme developer, based on an analysis of the costs and benefits of each option, and in consultation with the Department for Transport as project sponsor. In the case of Wendover, this decision has been supported by additional independent analyses. The decision to apply for a Transport and Works Order (TWAO), as a legislative vehicle for enabling the extended tunnel at Bromford, was taken by HS2 Ltd and did not require specific authorisation from the Department. The Bromford Tunnel TWAO application was received by the Secretary of State on 20 January 2022 and will now be assessed in accordance with standard TWAO processes and relevant legislation.