Between February 1 2001 and March 19 2002 - The Glasgow-born computer expert allegedly hacks into 97 US government computers from his home in north London.
He is accused of leaving 300 computers at US Naval Weapons Station Earle in New Jersey unusable immediately after the September 11 2001 terror attacks on America.
US prosecutors also allege he deleted files which shut down the US Army's military district of Washington DC network of more than 2,000 computers for 24 hours.
Mr McKinnon later denies causing any damage and says he was only looking for files that would prove the existence of UFOs.
March 19 and August 8 - Mr McKinnon is interviewed about his hacking by the UK's National Hi-Tech Crime Unit at the request of the US government.
October 31 - The District Court of New Jersey in the US issues a warrant for the computer expert's arrest.
November 12 - A US federal grand jury in Virginia indicts him on seven counts of computer-related crimes in 14 states, each count carrying a maximum sentence of 10 years in prison.
Paul McNulty, the US Attorney for the Eastern District of Virginia, says: "Mr McKinnon is charged with the biggest military computer hack of all time."
August 12 - The District Court of the Eastern District of Virginia issues another warrant for Mr McKinnon's arrest.
October 7 - The American government files a request for his extradition.
March 31 - A warrant for Mr McKinnon's arrest is issued by Bow Street Magistrates' Court.
June 7 - Officers from Scotland Yard's extradition unit arrest the computer expert at his north London home.
June 8 - He is granted bail when he appears at Bow Street Magistrates' Court.
May 10 - District Judge Nicholas Evans says Mr McKinnon should be recommended for extradition but passes the case to then Home Secretary John Reid for a final decision.
July 4 - Mr Reid signs an order for him to be extradited to the US.
April 3 - Mr McKinnon loses an attempt to appeal against his extradition at the High Court.
July 30 - The House of Lords, Britain's highest court, dismisses a further appeal bid by the computer expert.
August 25 - Mr McKinnon is diagnosed as suffering from Asperger's Syndrome, a form of autism.
August 28 - The European Court of Human Rights refuses an application to stay the extradition pending an appeal to the court.
September 13 - Then Home Secretary Jacqui Smith rejects a request from Mr McKinnon's legal team to stop the extradition on the grounds of his Asperger's diagnosis.
December 24 - The hacker's solicitor, Karen Todner, writes to Director of Public Prosecutions (DPP) Keir Starmer requesting that her client be prosecuted in the UK on a lesser charge.
January 23 - Mr McKinnon wins permission in the High Court to seek judicial review of Ms Smith's decision that his extradition should go ahead.
February 26 - The Crown Prosecution Service announces that it will not bring charges against the hacker in Britain.
March 16 - Human rights campaigner and former Middle East hostage Terry Waite calls on the US to drop charges.
June 9 - Lawyers for Mr McKinnon begin seeking a judicial review of Ms Smith's decision. His QC, Edward Fitzgerald, says the extradition could trigger psychosis or suicide and Ms Smith "underestimated the gravity of the situation".
July 6 - Lord Carlile, the Home Office's adviser on terror laws, says extraditing Mr McKinnon would be "cruel and unconscionable" when he could be prosecuted in the UK.
July 14 - Mr McKinnon makes a last-ditch bid at the High Court to force the Government into allowing a trial in the UK, challenging a refusal by the DPP to sanction a trial in this country.
July 31 - Two High Court judges give the results of the judicial review, saying that extradition was "a lawful and proportionate response to his offending".
Tory leader David Cameron joins the growing call for a review of extradition laws, saying Mr McKinnon is "a vulnerable young man and I see no compassion in sending him thousands of miles away from his home and loved ones to face trial".
August 2 - Mr McKinnon's mother, Janis Sharp, criticises the Home Secretary for linking her son to the September 11 terror attacks and the deaths of nearly 3,000 US citizens.
August 3 - Welsh Secretary Peter Hain says it would be better for Mr McKinnon to be "assessed in a British context".
September 9 - Former Labour minister Michael Meacher, ex-shadow home secretary David Davis and Liberal Democrat home affairs spokesman Chris Huhne say the Home Secretary "gave no ground" in the face of calls not to extradite Mr McKinnon.
October 9 - The High Court refuses permission for Mr McKinnon to appeal to the Supreme Court against his pending removal to America.
November 10 - Ms Sharp comes face to face with the Home Secretary and pleads with him to halt her son's extradition, saying he would "rather be dead" than sent to the US for trial.
November 12 - The Home Affairs Committee calls for a "comprehensive review" of the controversial treaty under which Mr McKinnon could be sent for trial.
November 26 - The Home Secretary rejects a last-ditch appeal for him to block the extradition, saying: "I have no general discretion".