Pope Francis' efforts to show that he's tough on clerical sex abuse have suffered a blow after a high-profile abuse survivor took a leave of absence from the pontiff's advisory commission.

Peter Saunders, a British advocate for survivors, had been highly critical of the slow pace of progress by the Vatican in taking measures to protect children and punish bishops who covered up for pedophile priests.

The Vatican said that during a meeting of the commission Saturday, "it was decided that Mr. Peter Saunders would take a leave of absence from his membership to consider how he might best support the commission's work."

His departure leaves just one other survivor of abuse, Marie Collins, on the commission, which was formed in 2013.