By what moniker is the controversial, proposed high-speed rail system between London and Birmingham commonly known?
What is HS2?
The initial plan is for a new railway line between London and the West Midlands carrying 400m-long (1,300ft) trains with as many as 1,100 seats per train.
They would operate at speeds of up to 250mph – faster than any current operating speed in Europe – and would run as often as 14 times per hour in each direction.
This would be followed by a V-shaped second phase taking services from Birmingham to Manchester and Leeds.
The Department for Transport says there will be almost 15,000 seats an hour on trains between London and the cities of Birmingham, Manchester and Leeds – treble the current capacity.