According to the Evening Standard newspaper, police managers will not risk sending officers out on bikes because they might be liable if the lid-less cops crashed sans helmets.
Police are not required to wear head protection in cars.
An Enfield police spokeswoman told the Evening Standard: "We have twelve bikes and we are looking at funding for more in the future. The bikes are not in use and won't be until we get the safety kits, which include the helmets."
Jenny Jones, Green Party member of the London Assembly, said: "Enfield has failed to see the huge benefits that having cycling police officers brings."