The Hammersmith Bridge will be closed to spectators for the annual Boat Race, turning away thousands from the popular vantage point.
The bridge has been closed to cars last April due to safety concerns, with the London Borough of Hammersmith and Fulham estimating repairs will cost £120m.
The council said today it had been asked by police to close the bridge for the yearly rowing race between Oxford University and Cambridge University on 29 March.
The race spans between Putney and Mortlake, passing under the bridge.
The decision was made to close the bridge off to pedestrians this year, after fears it was no longer safe for it to hold the mass of people expected on race day.
Conservative London Assembly member Tony Devenish said the closure showed why the bridge needed to secure funding for repairs immediately.
“With pedestrians and cyclists unable to use the bridge at the end of the month, there can be little doubt that this situation is getting worse, not better,” he said.
“This development will not only come as a massive disappointment to all those who were looking forward to watching the Boat Race, it will also raise concerns about the future of our bridge.”
The bridge was closed by Hammersmith and Fulham council after it found “critical faults” last year.
TfL has pledged to spend £25m on the repairs, which are expected to take three years to complete, with the rest needing to come from central government.
A temporary bridge may be constructed for motorists in the meantime, with TfL currently drawing up the plans.