Lindsay Lohan's lawyer has been branded a liar after claiming she suffered a concussion from her car accident last June.

The 26-year-old troubled starlet - who is set to go on trial on March 18 for violating her probation after allegedly lying to police about driving her Porsche when she crashed on the Pacific Coast Highway last summer - was in no state to be questioned by police at the time because she had a head injury, according to her New York attorney Mark Heller, who was labelled ''incompetent'' by Judge James Dabney yesterday.

But law enforcement officials told gossip website RadarOnline.com, "The doctors who treated Lindsay on the day of her car accident last summer didn't diagnose her with a concussion. She suffered no injury to her head whatsoever. She did have bruised ribs, and she was very sore, but that was her only significant injury. Lindsay had a CT scan of her head, neck, and spine and there was no injury. Not only that, but Lindsay went back to work after leaving the hospital. For Mark Heller to claim that Lindsay had a concussion is an absolute and blatant lie. When she was questioned by cops at the emergency room, she wasn't denied any medical attention because of them."

During a press conference after his appearance in court yesterday, Mark claimed, "My client suffered a concussion, and never should have been questioned by the police. She was basically held against her will and forced to answer questions."

Lindsay's estranged father Michael Lohan wants her to hire a new lawyer as he believes Mark is a "loser." The actress has already rejected a plea deal during the pre-trial as she doesn't want to go to rehab and could face significant jail time if the judge determines she violated her probation, which she has been on since July 2011 after being found guilty of stealing a necklace.