The guardrails at the tourist hotspot – where three people were run over and killed in last week’s terror attack – were taken down in 2010.
The move left pedestrians vulnerable to vehicles veering off the road.
“At the very least [barriers] would have slowed [the terrorists’ van] down”
Will Geddes, security expert
Hundreds of miles of railings were scrapped under the Better Streets initiative and Transport for London’s (TfL) Streetscape.
Guardrails have been removed from busy areas including Tower Bridge road, Kings Cross, Baker Street, Hyde Park, The Strand and Piccadilly.
Last weekend a van hired by extremists Khuram Butt, Rachid Redouane and Youssef Zaghba mowed down pedestrians on London Bridge.
Concrete barriers were hastily put in place on the bridge to stop any repeat.
But TfL said it had no plans to halt the Guardrail Removal Programme.
A spokesman said: “Guardrail was removed in 2010 as part of a programme to improve safety – preventing vulnerable road users such as cyclists becoming trapped between railings and traffic – as well as reducing street clutter across London.
“Guardrail is not designed to withstand vehicle impact. For this, specialist barriers are required. The programme will continue.”
A 2010 report by TfL seen by Daily Star Sunday said guardrails should be removed from roads because they looked “ugly”, “cluttered” and “increased maintenance”.
It also said their upkeep was a financial burden, and could hinder people wanting to get in and out of cars, buses and taxis.
It added: “We have a presumption against the use of pedestrian guardrails in new schemes and are actively removing guardrails where evidence from a safety audit demonstrates they are not required.”
But a report by the London Road Safety Unit claimed guardrails cut the number of accidents by 27%.
He ploughed in £220million of public money in a bid to create “oases” in London.
The Foreign Secretary, hotly tipped to be the next PM, said he wanted to minimise traffic lights and remove railings and pedestrian crossings.
In 2012, he said: “I have removed a substantial number of guardrails along pavements, making it easier and safer for pedestrians to cross, and stripped out other unnecessary street clutter.”
He added that he would “continue to work” with council chiefs to scrap guardrails.
But security expert Will Geddes said railings would have hampered the London Bridge terrorists.
He said: “Whether or not these railings would have stopped a vehicle dead in its tracks, at the very least they would have slowed it down, giving people vital seconds to flee.”
He added: “Whether it’s a car or someone coming at you with a knife, street furniture or railings is a physical barrier you can put between a pedestrian, car or potential attacker, so that the victim isn’t the first point of impact.
“In light of the recent terror attacks on London Bridge and Westminster, traffic calming measures need to be put in place in all busy areas.”