Thames Valley Police said 20 year-old Jed Foster has also been charged with theft of a quad bike in relation to the incident.
Nine other suspects aged between 13 and 30 have been released on bail.
Chief crown prosecutor Jaswant Narwal, said: “Following the death of PC Harper in Berkshire, the Crown Prosecution Service has today authorised Thames Valley Police to charge Jed Foster, 20, with murder and the theft of a quad bike.
“We will offer to meet with PC Harper’s family to explain the basis of the decision we have made following a lengthy review of the evidence available.”
“May I remind all concerned that criminal proceedings against Mr Foster are now active and that he has a right to a fair trial. It is extremely important that there should be no reporting, commentary or sharing of information online which could in any way prejudice these proceedings.”