It is the 30th anniversary of the death of pioneering Arab cartoonist Naji al-Ali. He was shot to death as he walked to his office in London.

Ali’s political cartoons were scathing of both Arab governments and Israel, and his most famous character, Handala, remains a symbol of Palestinian resistance to this day.

His killers have never been caught. Now British police and Ali’s family have launched a new appeal for information.

Al Jazeera’s Paul Brennan reports from London.