Prime Minister concedes costs have spiralled but argues 'poor management has not detracted from the fundamental value of the project'
Transport Secretary Grant Shapps tells MPs full London-Birmingham services will not begin until 2031
Move calls into question whether the controversial £50bn infrastructure project will go ahead
Additional High Speed Rail funding will go towards HS2 Woodland Fund to plant new native trees along route between Birmingham and Crewe
High speed rail line linking London to West Midlands becomes first infrastructure project to be awarded BREEAM accreditation