The current HS2 funding envelope is £55.73bn (at 2015 prices), as set out in the 2015 Spending Review settlement. This is split between phases, with Phase One set at £27.18bn and Phase 2a&b at £28.55bn.
At the 2013 Spending Review the HS2 funding envelope was at £50.1bn (at 2011 prices). This funding allocation was split as follows: Phase One £21.4bn, Phase 2 £21.2bn and Rolling Stock £7.5bn. Spending Review 2013 was the first time a long term funding envelope was established for the HS2 network.