Sepang, Malaysia: Fernando Alonso on Thursday muddied the waters still further about his mysterious crash in testing when he said he remembers every detail but that the cause remains unknown.

The two-time world champion said a freak steering lock-up caused him to crash his McLaren in Barcelona in February, and that he only lost his memory when given medication afterwards.

But he said exhaustive tests had been unable to locate the cause of the steering failure, a concerning revelation before he returns to racing this week in Malaysia.

Speculation swirled that Alonso may have blacked out or suffered an electric shock before the February 22 accident, which was into an inside wall at a relatively low speed.

One report said the Spanish driver, 33, believed it was 1995 when he came round, and that he was still a teenager racing go-karts.

But Alonso said: “I went to the hospital in good condition. There is a time that I don’t remember, from 2pm to 6pm, something like that.

“Everything was normal due to the medication they give you to go into the helicopter and do some tests in the hospital.

“It was normal. I didn’t wake up in 1995, I didn’t wake up speaking Italian. I remember the accident and I remember everything that following day.”

Alonso has been cleared to take part in this week’s Malaysian Grand Prix after missing the season-opener in Australia to avoid the risk of a second concussion.

But questions remain over his MP4-30 car, which has been fitted with extra sensors after none of the data collected in Spain was able to explain what happened.

“I’m sure we’re missing something on the data acquisition which we’ll spot in 10 years’ time when the knowledge is available,” he said, answering media questions about the crash for the first time.

“I have zero doubts, zero concerns [about racing],” he added.