Rory Stewart has pledged to fund the £95M repair cost for Hammersmith Bridge if he becomes Mayor on 7th May.
Stewart - who is running as the independent candidate - said he would underwrite the full repair cost from Transport for London's (TfL's) capital account in his first week in office.
He added that he would ensure the temporary bridge design allows emergency vehicles to cross, so ambulances can bring patients to Queen Mary’s and Charing Cross hospitals.
The bridge was closed in April last year after "critical faults" were discovered.
This week TfL asked for West London residents’ views on a proposed temporary pedestrian/cycle bridge which would allow the main bridge to shut for the repairs.
Stewart has also pledged to implement a “Boats, Bikes and Buses” action plan to deal with the effects of the closure.
This would include extending river boat services to Barnes and Hammersmith from Putney and additional Santander bicycle docking stations on the Barnes peninsula.
Finally, he said an on-demand bus service would provide better access for Barnes residents to East Putney and other stations.
Stewart described the bridge as “a vital piece of infrastructure”.
He added: “Yet again Sadiq Khan has passed the buck, blaming Hammersmith & Fulham Council, and central government. Yet again he has failed to take responsibility for something that is eminently within his control.
“If I was mayor I would take action on day one, and underwrite the cost of repair. I would ensure TfL takes responsibility for bringing the bridge back into service as quickly as possible and put an end to the current excuses. London deserves better, and it’s time for action.”