Fernando Alonso crash: McLaren-Honda driver faces further hospital tests following accident described as 'strange' by Sebastian Vettel

Alonso was lucky to escape serious injury after hitting the barrier at the high-speed Turn Three

Alonso is taken form his stricken McLaren-Honda to an ambulance (Getty Images)

Fernando Alonso faces further hospital tests after escaping serious injury in a freak crash on the final day of running at the pre-season test in Barcelona yesterday.

The crash saw him airlifted to hospital where he was diagnosed with concussion. The Spaniard was kept in overnight and well be checked again before a decision is made on whether he should be released.

The 33-year-old McLaren-Honda driver, who was behind the wheel for just the fourth time since leaving Ferrari for the Woking-based outfit, was rounding the 150mph Turn Three when he suddenly veered right and slammed into the barrier side-on.

Alonso was initially taken by ambulance to a medical centre at the Circuit de Catalunya, before being airlifted to the nearby local hospital for further tests including a CT and MRI scan.

Fernando Alonso behind the wheel of his McLaren-Honda (Getty Images)

A decision was made to keep the two-time world champion in overnight “as a precaution”, but despite the Spaniard being kept in intensive care, McLaren say this is simply a precaution and that Alonso is talking freely and has no major injuries.

Alonso's manager later tweeted a picture of the driver in his hospital giving fans the thumbs up to signal he is ok, and thanked them for their supportive messages during his brief recovery.

The accident happened shortly before the lunchtime interval on Sunday, but the cause of the crash at this stage remains unknown. McLaren racing director Eric Boullier denied that the crash was caused either by Alonso suffering an electric shock or that he passed out at the wheel, but Sebastian Vettel’s account of the crash leaves many question to be answered.]

"Fernando's accident was just one of those things that happens in testing,” said Boullier.

"Fortunately, he's fine, but was concussed during the accident, which therefore required an overnight stay in hospital as a precaution. That's normal practice after a concussion.

"Inevitably, some media reports have sought to exaggerate the severity of the incident - it was just a normal testing accident."

Alonso is transported from the medical centre at Catalunya to a helicopter (Getty Images)

But Vettel, who was behind the McLaren-Honda when it went off, admitted that the crash was not at full speed and that it looked “strange”.

"The speed was slow - maybe 150kph,” said the four-time world champion Vettel. “Then he turned right into the wall. It looked strange."

McLaren continue to be hampered by reliability problems that limited their running in Barcelona to just 104 laps across the four days. In comparison, Mercedes’ Nico Rosberg completed 131 laps on Sunday alone.

Alonso is transferred from the medical centre to the helicopter after crashing (GETTY IMAGES)

They continue to be troubled by a faulty seal on the MGU-K part, on of the energy recovery systems on their new car, while the crash meant that extensive checks and repairs were required that saw the team end their running early despite the afternoon session still taking place.

Boullier added: "While the car wasn't particularly badly damaged, it was enough of an impact to warrant quite a lengthy check of the gearbox and power unit systems.

"Given the time needed to carry out such an analysis, we decided to bring the curtain down on our test a few hours earlier than anticipated.

"It's been a tough week for the whole team, but we'll be back, and pushing harder than ever, in Barcelona next week."