McLaren confirms no injuries, but questions are asked over what caused him to leave the circuit.
Fernando Alonso spent Sunday night in hospital after his unexplained accident during the final day of the first Formula One test at Barcelona.
Alonso was airlifted to hospital following the incident, which took place between Turns 3 and 4 of the Circuit de Catalunya just before lunchtime.
His McLaren team has confirmed that the Spaniard has undergone a full CT scan in hospital and has no injuries. A spokeswoman added: "He is fine, that's all I can say."
McLaren has since shelved plans to send Jenson Button out in the repaired car, which only appeared to have sustained relatively cosmetic damage, and has packed up in preparation of the next test here on February 26.
McLaren tweeted: “That’s the end of our programme here at the first Barcelona test. Thank you for all your messages of support for Fernando.”
A photographer’s eyewitness report has suggested that the way Alonso left the track was unusual in that he bounced along the grass, scraping the wall, for little apparent reason.
His car eventually came to rest on the approach to Turn 4, where marshals and medics quickly attended to him. Photographs of the scene showed him to be lying on the ground next to his car.
McLaren’s test had been blighted by problems with the MGU-K energy recovery system of its Honda power unit.