Bottas posted a best lap of 1 minute, 28.496 seconds in the afternoon at the Silverstone circuit, with the Finnish driver less than a tenth of a second faster than Hamilton.
They were followed by Ferrari duo Kimi Raikkonen and championship leader Sebastian Vettel, who is 20 points ahead of Hamilton at the top of the standings going into Sunday’s race.
The Red Bulls of Max Verstappen and Daniel Ricciardo had gone faster than their Ferrari counterparts in the morning, but they were behind the Italian constructor in the second session.
Renault’s Nico Hulkenberg made an impressive performance and to take seventh overall, finishing almost a second clear of Jolyon Palmer in the sister Renault car down in P18, as Felipe Massa put Williams’ updates to good use en-route to P8 despite suffering a spin at Chapel.
Fernando Alonso once again led McLaren into the top 10 with its upgraded Spec 3 Honda power unit, finishing ninth overall. Esteban Ocon completed the front end of the order in P10 for Force India.