Sources at Crossrail are warning that the new Elizabeth Line might not be open between Paddington and Liverpool Street until 2021, after fresh revelations about dynamic testing. It is now being claimed by one source that dynamic testing – running trains under power through the central section – is ‘proving more difficult than was first thought. It all depends on how dynamic testing goes between now and the end of this year: the last quarter of this year will be a critical period.’ Caroline Pidgeon, who chairs the London Assembly Transport Committee, said: ‘Londoners will be hugely disappointed and frustrated.’