JEDDAH, Saudi Arabia - A source close to Saudi Arabia's rulers has given further details of how Mohammed bin Nayef, the former crown prince, was summarily removed from his post last month.MbN, as he is known, was dismissed by the royal family "in the higher interests of the state" because he was incapacitated by morphine and cocaine addiction, often falling asleep at public events after he became crown prince in 2015, the source told Reuters in an interview.His addiction was a legacy of an Al Qaida assassination attempt in 2009 that left shrapnel in his body."MbN has a lot of respect among us as a crown prince and as interior minister but there are higher interests for the state which are more important than social position or status," the source told Reuters.Reuters was unable to reach MbN for comment. Sources close to him said he would not comment and has remained in his palace in Jeddah since he was removed in June. The sources acknowledged MbN's addiction to morphine but said it was used as a pretext to speed up the elevation of Mohammed bin Salman, the king's 32-year-old son, to be next in line to the throne.Reuters was unable to confirm independently the specific drugs MbN used to treat his health problems.The source, who has knowledge of palace thinking, expanded on an account by Reuters earlier this week saying MbN was pushed aside because of his drug addiction.The drive to remove MbN came from the king and the Allegiance Council, the 34-member body of senior princes supposed to approve and monitor the king and his anointed successors, the source said.He denied that MbN was the victim of a palace coup by King Salman's ambitious young son, known as MbS, in a hurry to clear his path to the throne while his ailing 81-year-old father still occupies it.He also denied suggestions by a Saudi source that the king was preparing to abdicate in favor of MbS, possibly as soon as September."This scenario is out of the question and it has not been discussed or proposed," the source said.MbN had struggled with drug addiction for years dating back to when the late King Abdullah was in power, the source said."King Abdullah talked seriously to him about (his addiction). MbN confirmed that it was because of the assassination attempt. He said he needed to use the painkillers to relieve the pain from the shrapnel in his body. He promised King Abdullah to end this and be under medical supervision."The source confirmed Reuters' report that MbN traveled to Switzerland on many occasions for treatment but to no avail."The king told him clearly: if you return to addiction you will be removed," the source said.King Salman decided that keeping MbN would be harmful to the country, the source said.The source denied an assertion by a source close to MbN that the former crown prince was under house arrest, and that his bodyguards had been replaced by a new security detail.