The tunnel is part of a new Tesco supermarket complex being built in Gerrards Cross. Ipswich firm Jackson Civil Engineering is the main contractor on the £20.3 million design and build contract to build a 300 m-long tunnel over the track.
Mr Hardy said: 'The public needs to feel totally confident that the reasons for the collapse are fully understood and that effective remedial action to guarantee their safety has been taken.
'The only way we can be sure of that is for full details of the engineers' report to be published, and for there to be a public inquiry into all the circumstances.'
'This ill-fated and seemingly interminable project looks destined to blight the lives of people around the construction site and the village for far longer than originally planned.
'If Tesco decide to continue with the project we will need to be assured that any future construction work will not prejudice the safe running of the railway.'