McLaren's woes continue as Fernando Alonso suffers two breakdowns in Barcelona

Kimi Raikkonen posted a best time of 1:18.634

Alonso's McLaren has shown no signs of improving following continual engine problems (Getty)

McLaren's woeful pre-season continued on the final day of the Barcelona test as Fernando Alonso's MCL32 twice ground to a halt at the Circuit de Catalunya.

The former world champion's team and engine suppliers Honda have been plagued by problems which showed no signs of improving, with the first race of the season in Australia just over two weeks away.

Alonso's car stopped twice on the track on Friday's morning session to add to the two red flags on Thursday as the team were again robbed of valuable track time ahead of the Melbourne race.

The first stoppage came just over halfway into the morning session, with Alonso's car eventually taking its now customary place on the back of the recovery truck after a short break.

But when the Spaniard returned to the track with a little over an hour of the session left it stopped again almost straight away.

The double world champion had blamed McLaren's woes on engine supplier Honda earlier in the week, and the Japanese manufacturer admitted his Friday setbacks were caused by the same electrical problem which hit team-mate Stoffel Vandoorne on Thursday.

A Honda spokesperson said: "Fernando has stopped out on track with the same issue that Stoffel encountered yesterday - intermittent electrical shutdown.

"Various electrical components in the PU and chassis were changed overnight, and the team are making further changes to eliminate variables and identify the source of the problem."

Alonso returned to the track with just over two hours of testing remaining, with his team posting on Twitter: "After encountering another electrical issue, we carried out several fixes to the car. Our afternoon run plan now resumes."

Former world champion Sebastian Vettel had set the best time of testing so far on Thursday with a lap of one minute 19.024 seconds, but on Friday morning he was usurped by Ferrari team-mate Kimi Raikkonen.

The Finn posted a best time of 1:18.634 to top the morning session, but had concentrated on race simulations after lunch before his Ferrari broke down in the chicane.

Second quickest in the morning was Red Bull's Max Verstappen in 1:19.438, but his afternoon track time was restricted as his team battled with an issue with the car's turbocharger.

Carlos Sainz set a surprise third best time in the morning in the Toro Rosso and he lowered that to 1:19.837 before he too encountered problems and stopped on track late in the afternoon.

Romain Grosjean had an eventful morning session as he lost the rear end of his Haas and ended up in the gravel and later stopped on the back straight, his two red flags sandwiching those of Alonso.

New Mercedes driver Valtteri Bottas' 1:19.845 was good enough for fourth ahead of his team-mate Lewis Hamilton, who took over duties after lunch, the Renault of Nico Hulkenburg and Force India's Sergio Perez.

Jolyon Palmer was making the most of Renault solving their reliability issues to post the eighth best time ahead of Canadian Lance Stroll, the Formula 3 champion putting his recent crash spree behind him to clock up over 100 laps for Williams.

Alonso, Grosjean and Sauber duo Marcus Ericsson and Pascal Wehrlein rounded out the timesheets.