Fernando Alonso was taken to hospital after being concussed in a heavy crash that brought a premature end to a test run in Barcelona on Sunday and created further angst for McLaren-Honda, the Spaniard’s team, before the Formula One season gets under way in Melbourne on 15 March.

The double world champion, who received CT and MRA scans, will remain in hospital overnight as a precautionary measure, following the accident on the final day of the second testing session at the Circuit de Catalunya.

McLaren’s racing director, Eric Boullier, said: “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 rejoined McLaren from Ferrari at the end of last year to enhance his chances of winning a third title, but the team have been beset by problems in testing. In Jerez this month they managed a mere 12 laps in the opening two days and since Thursday in Barcelona they have had problems because of a faulty seal on one of the car’s engine recovery systems.

On Friday Alonso managed 59 laps despite the MP4-30’s reliability issues. But he warned: “We will arrive in Australia hoping Australia was in June or July but it’s in March, and I don’t know if we will arrive completely ready.” And on the same day Boullier said they were “50% behind” on their scheduled testing programme.

On Sunday Alonso was the slowest of the nine drivers who took part. His accident happened when the right-hand side of his car hit the wall on the exit of the 150mph Turn 3. Considering the car’s velocity in the accident, it was not badly damaged but plans for his team-mate, Jenson Button, to run in the afternoon were abandoned.

Sebastian Vettel, the four times world champion who replaced Alonso at Ferrari, was behind Alonso at the time of the accident and said: “The speed was slow – maybe 150kph. Then he turned right into the wall. It looked strange.” On Sunday evening McLaren were still investigating the cause of the accident.

Boullier said: .“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.”

McLaren completed 104 laps in four days at Barcelona. That total was surpassed – on Sunday alone – by Mercedes, Williams and Lotus, all using Mercedes engines.

McLaren are banking on their renewed partnership with Honda – the alliance that brought them their greatest years in the hands of Ayrton Senna and Alain Prost – to deliver once again. They remain one of the greatest names in Formula One, but have not won the constructors’ championship since 1998 and last season were beaten into fifth position, some 520 points behind Mercedes.

On Sunday Romain Grosjean (Lotus) was the fastest driver, though his time was set on the super-soft Pirelli tyre. He had taken over from his team-mate Pastor Maldonado. The most impressive performer was again Mercedes, who remain strong favourites to retain their double world championship. Nico Rosberg, whose car wore the medium tyres, thought to be about two seconds a lap slower than the super-softs, was still only 0.254sec slower than Grosjean. Rosberg also did more laps (131) than any other driver.

Williams, Red Bull and Ferrari all look in the mood to step up their challenge to Mercedes. But McLaren face yet another very difficult year.