Some 159 sex offenders being managed by authorities in London are missing, figures released show.
Ninety six are believed to be living abroad while the rest are wanted for breaching notification requirements.
Conservative London Assembly member Tony Arbour said Londoners would be alarmed that criminals “such as rapists and paedophiles” were being lost.
The Met Police says the number varies because the information is dynamic and will change as arrests are made.
Under the Multi-Agency Public Protection Arrangements (Mappa), the national probation service, HM Prison Service and the Met are responsible for managing serious sexual and violent criminals, once they complete their sentence.
The figures were released to Mr Arbour under the Freedom of Information Act by the Met.
In the response, the force said it believed 96 of the offenders were living abroad, with many having returned to their “home” country.
Mr Arbour said: “Londoners will be alarmed that the authorities are losing serious criminals such as rapists and paedophiles who may commit further crimes.
“If some of the ‘wanted’ offenders have left the country, as the police say, what is to stop them from re-entering our borders?”
In February 2012 the Met said it had lost track of 123 sex offenders.
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