There is not a fixed time limit. I will make two more points if I may.
When the noble Lord, Lord Framlingham, said that the case for HS2 when it started was on speed and not capacity, that was completely untrue. I published the White Paper on HS2 in March 2010, the opening words of which were,
“the Government’s assessment is … That over the next 20 to 30 years the UK will require a step-change in transport capacity between its largest and most productive conurbations … alongside such … capacity, there are real benefits for the economy and for passengers from”—