London police on Saturday charged a 29-year-old homeless man with causing grievous bodily harm and possessing an illegal knife he used to stab a mosque leader during prayers.

British police officers stand on duty outside the London Central Mosque near Regent's Park in London after a man was stabbed in the mosque. (Photo: AFP)

Suspect Daniel Horton stabbed London Central Mosque's muazzin Raafat Maglad during daily prayers on Thursday.

London police quickly ruled out a terror motive.

Maglad was treated at a London hospital and returned to the mosque for Friday's evening service with his arm wrapped in a sling,

"I forgive him. I feel very sorry for him," Maglad told reporters on Friday.

"To me, as a Muslim, I don't need to put any hatred in my heart."

Several regulars at the Regent's Park area mosque in northwest London said they had seen Horton attend a few services in the past year.

Horton will appear at Westminster Magistrates' Court for a preliminary hearing later Saturday.