Question: when did the last trolley bus run in london
[{'answer': '8 May 1962', 'provenance': [{'wikipedia_id': '31197885', 'title': 'Trolleybuses in London', 'start_paragraph_id': 7, 'start_character': 136, 'end_paragraph_id': 7, 'end_character': 146, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}]