 He stated that HS2 passengers travelling from the North of England to continental Europe would be able to transfer easily from Euston to St Pancras by London Underground in order to continue their journey on HS1.He also recommended that alternative plans should be drawn up to link the high-speed lines in the future.The then Mayor of London, Boris Johnson, proposed that an HS1-HS2 link should be provided by boring a tunnel under Camden to reduce the impact on the local area.