text: Subhan Shafiq stepped down as Milton Keynes mayor after describing the man as being of "good current character".
  This helped the driver, Mr Shafiq's friend, to get a taxi driver's licence.
  Milton Keynes Council leader Peter Marland said Mr Shafiq should examine his conscience over whether he could even continue as a councillor.
  Mr Marland, Labour leader of the council, said: "He resigned to protect the reputation of the council but I think it is very difficult for him to remain and keep the trust of the public after advocating for someone who has been convicted of rape.
  "He must examine his own conscience on this."
  Mr Shafiq, a Liberal Democrat, had described his "friend", who had been convicted of four sexual assaults, as being of "good current character".
  But earlier this month a member of the public raised concerns about the driver and his licence was revoked.
  The council claimed it had "taken rapid steps" to keep passengers safe.
  Mr Shafiq said in a previous statement he had resigned as mayor "with deep regret".
  The driver had been issued with a licence in September 2011, despite councillors knowing of his four convictions, for which he had served a "substantial" custodial sentence.
  He had received a "very strong" character reference from Mr Shafiq, who became mayor in June.
  The driver's convictions were discussed again in 2012 and his licence was temporarily suspended, but this ban was later "inexplicably" lifted, the council said.
  Seven other drivers who give the council "cause for concern" have been identified as part of a detailed review of licence holders.
target: A mayor who resigned after a taxi driver he vouched for was found to have a rape conviction has been urged to leave the council altogether.