Heavy lorries cross Tower Bridge breaking the 18-tonne weight restriction up to 18 times a day according to Transport for London which is mounting a crackdown.
Transport for London is teaming up with the police to stop drivers of heavy goods vehicles causing potential damage to the historic bridge.
TfL claims that many of the culprits are driving foreign registered vehicles and crossing the bridge at night.
Engineers say that the 113-year-old structure was not designed for the freight traffic which rolls across it today.
Last week police officers and TfL staff staged the first in a series of night operations to stop the offending HGVs. Drivers breaking the limits were warned that their companies would be contacted in the cases of repeat offenders.
"We are determined that the most famous bridge in London's skyline will not be damaged by the ignorance of a few drivers," says Patrick Troy, head of TfL traffic enforcement.
"This operation will educate those who may be unaware of the restrictions while deterring those who think they can get away with ignoring them."
The bridge is owned by the City of London Corporation. City survey Ted Hartill says: "Engineers believe the continued passage of large vehicles is likely to damage the bridge and therefore we welcome the attempts by the TfL and the Police to restrict movements of such vehicles.
Transport for London has been enforcing the weight restriction at Tower Bridge using digital technology since July 2006. Vehicles breaking the weight limit are sent penalty charge notices, but some foreign registered vehicles avoid paying penalties because of difficulties of cross border enforcement under current laws.
Contraventions by foreign registered vehicles account for approximately 60 per cent of the total.
In July, August, September and October the most prolific offenders on Tower Bridge were foreign registered vehicles, with one driver alone accumulating 21 PCNs.