BARCELONA, Spain, April 17, 2008 (AFP) - Heavy rain Thursday spoilt the fourth and final day of Formula One testing at the Montmelo circuit, which will host the fourth grand prix of the season on April 27.

Times recorded by the Ferrari of reigning world champion Kimi Raikkonen, Heikki Kovalainen in a McLaren, Robert Kubica of BMW Sauber and Nelson Piquet Jr in a Renault were at least three seconds slower than those of the first three days.

Only Australia's Mark Webber, in a Red Bull, put in a respectable time, of 1min 21.953secs in the morning, before the rain began lashing the track.

Renault's two-time world champion Fernando Alonso expressed satisfaction with modifications to his car, which allowed him to record the best time of the week on Wednesday.

But he remained cautious about prospects for the rest of season, noting that the French team was in fourth place in the constructors race, behind Ferrari, McLaren and BMW.

After a poor start to the season, Alonso, who gave way to Piquet for testing on Thursday, recently threatened to quit the team at the end of 2008 unless he had a more competitive car.

Thursday's times:
1. Mark Webber (AUS/Red Bull) 1:21.953 (37 laps)
2. Heikki Kovalainen (FIN/McLaren) 1:23.589 (34)
3. Kimi Raikkonen (FIN/Ferrari) 1:23.619 (34)
4. Robert Kubica (POL/BMW Sauber) 1:24.715 (32)
5. Jason Button (ENG/Honda) 1:24.873 (32)
6. Kazuki Nakajima (JPN/Williams) 1:24.927 (62)
7. Nelson Piquet Jr (BRA/Renault) 1:26.100 (61)
8. Jarno Trulli (ITA/Toyota) 1:32.150 (18)