Question: who was voted the greatest briton of all time by the uk public in a bbc poll in 2002
[{'answer': 'Sir Winston Churchill', 'provenance': [{'wikipedia_id': '200958', 'title': '100 Greatest Britons', 'start_paragraph_id': 7, 'start_character': 13, 'end_paragraph_id': 7, 'end_character': 34, 'bleu_score': 1.0, 'section': 'Section::::Full list.\n'}]}]