'Approved' here means that a bill was passed in the UK Parliament, similar to the High Speed Rail (London - West Midlands) Act 2017

NPR was planned, but cancelled before approval.

The Northern Powerhouse Rail (NPR) was a proposed high-speed rail project that aimed to improve connectivity and create economic growth in the north of England. However, in 2021, the UK government announced the cancellation of the NPR project, citing concerns over its estimated cost of up to £100bn.

HS2 Phase 2a was also planned and cancelled.

In 2021, the UK government announced the cancellation of the HS2 high-speed railway link to Leeds, which was intended to connect the city to other major cities in the country, including London and Birmingham. The cancellation came as part of a review of the HS2 project and was met with disappointment from local leaders in the region who had advocated for the link.

The connection could run through Manchester, or direct to London through Birmingham.

'High-speed' is here arbitrarily defined as trains travelling over 250km/h (to capture the difference between current fast rail in the UK and planned/operational high-speed rail, ie HS1 and HS2 phase 1. Notice that by this definition domestic services on HS1 are not high-speed)