What's your number? http://efukt.fun/ efukt.com SIR – Sir David Higgins was reported as saying that he only took the role of chairman of HS2 because the Government assured him it was committed to seeing the project through. It would have been sensible for him also to seek an assurance that the business case remained valid in the face of factors that may have been wrongly weighted, changed, or not yet taken into account (Letters, September 27).