Clifford, 71, was at North East Surrey Crematorium in London, where his brother Bernard’s funeral took place.
The disgraced PR guru wore a navy suit, pink shirt and sunglasses, and arrived and was taken away in a prison van.
Clifford was jailed for eight years after being convicted of a string of indecent assaults, carried out between 1977 and 1984.
The Ministry of Justice said it does not comment on individuals, but a spokeswoman said prisoners need to apply to attend a funeral and the prison assesses risk to the public and also looks at the prisoner’s relationship to the dead person.
If permission is granted, the prisoner is normally escorted to the funeral by staff.
The former celebrity agent, who branded his accusers “fantasists”, remained defiant ahead of his sentencing, saying: “I stand by everything I have said in the last 17 months.”
Clifford has lodged an appeal against his sentence.