The Editorial Intelligence Power of the Commentariat report will be published next month.
It praises Toynbee for 'combining forensic journalistic research with heart-on-sleeve opinion'. Editorial Intelligence CEO Julia Hobsbawm said: 'Her columns resonate in Whitehall and beyond.'
The Sun's Trevor Kavanagh and The Sunday Times' Irwin Stelzer come in at numbers two and three respectively. BBC political editor Nick Robinson is at number four for his well-read blog.
Hobsbawm teamed up with Weber Shandwick, the Reuters Institute and the City of London Corporation to produce the report.
Editorial Intelligence polled 'opinion formers and self-selecting interested parties' across politics, business, media, and academia, as well as members of Facebook group 'Keep up with the Commentariat'.
The full report will include the most influential leader pages and political blogs.