It took 17 days for the news of Nelson's victory at Trafalgar to reach London

"It took a full seventeen days for news of Nelson’s victory in 1805 at the Battle of Trafalgar to reach London. The news had travelled at 2.7mph.
News of the 1891 Nobi Earthquake in Japan travelled at 246mph, taking one day to reach London.
And in 2008 it took just one minute for news of the Sichuan earthquake to reach – London, travelling at 204,000mph."

Source:  Blog post by Martin Weigel, 15th July 2013

Note - I'm not sure of the original source, but I think it might be Michael Stillwell, A Farewell To Alms: A Brief Economic History Of The World

See also - 'It took radio 38 years to reach 50 million people