The executive director of the campaign group 38 Degrees has been sacked after the board concluded he had provided illegal drugs to staff.
A statement from Srabani Sen, chair of the organisation, said David Babbs had been dismissed for gross misconduct.
"He was found to have provided illegal drugs to staff members, behaviour which failed to meet the standards expected of him as executive director," she said in the statement.
"Separately the board has commissioned an independent external investigation into a number of other allegations which have been made relating to David’s conduct.
"We’ve launched this investigation to determine the facts about what happened, and are committed to seeing this process through."
The statement said the allegations did not relate to any alleged financial impropriety and did not threaten the financial position or assets of 38 Degrees.
"The board considers the welfare of our staff to be one of our highest priorities," the statement concluded.
"We are also conducting a review to ensure our processes and procedures live up to that commitment.
"We’re working closely with our senior leadership team to ensure 38 Degrees continues to champion people power, at a time in British politics when our voices are needed more than ever."
Third Sector was unable to reach Babbs for comment but he told The Daily Telegraph newspaper that he was glad there was going to be an independent investigation and he believed he would be cleared of the allegations under review.
38 Degrees was founded in 2009 by a group of activists and funders concerned about the state of democracy in the UK.
Babbs led the organisation from when it was launched, according to his LinkedIn profile.
Last year, the organisation had an income of almost £5.7m.