Ferrari driver Fernando Alonso has posted the fastest lap in a second practice session at Monaco which was hampered by difficult conditions and many tyre changes.

With half an hour of the session gone there had been just one full lap completed, but in a frantic end to the session the Spaniard managed the quickest time of 1:18.482.

He held the lead by nearly half a second from Lewis Hamilton after extending the gap with his last lap, as the Brit posted a time of 1:18.901 for Mercedes.

Reigning champion Sebastian Vettel was third for Red Bull, while the next-best Briton was Jenson Button in eighth for McLaren.

Full standings to follow:

1. Fernando Alonso (Ferrari)
2. Lewis Hamilton (Mercedes)
3. Sebastian Vettel (Red Bull)
4. Jean-Eric Vergne (Toro Rosso)
5. Valtteri Bottas (Williams)
6. Sergio Perez (Force India)
7. Nico Hulkenberg (Force India)
8. Jenson Button (McLaren)
9. Daniel Ricciardo (Red Bull)
10. Kevin Magnussen (Mclaren)
11. Felipe Massa (Williams)
12. Daniil Kvyat (Toro Rosso)
13. Adrian Sutil (Sauber)
14. Pastor Maldonado (Lotus)
15. Esteban Gutierrez (Sauber)
16. Romain Grosjean (Lotus)
17. Kamui Kobayashi (Caterham)
18. Jules Bianchi (Marussia)
19. Max Chilton (Marussia)
20. Nico Rosberg (Mercedes)
21. Marcus Ericsson (Caterham)
22. Kimi Raikkonen (Ferrari)