Ben Kernighan has quit as the chief executive of the National Union of Students after ten months.
Kernighan, whose previous job was deputy chief executive of the NCVO, where he had spent 15 years in total in a number of positions, joined the NUS in July of last year.
His Twitter profile now describes him as freelance.
Peter Robertson, managing director of NUS Services, the commercial arm of the organisation, will lead the NUS until a replacement for Kernighan is found.
A NUS statement says: "After careful consideration Ben Kernighan has decided that he does not wish to continue in his position as chief executive of NUS and has now left the organisation.
"Ben successfully led a complex process of bringing together the disparate parts of the group under one new set of terms and conditions. He led the organisation to a number of policy successes around higher and further education funding and regulation as well as wider policy wins including winning concessions to the Lobbying Act.
"He also oversaw the successful launch of the National Society of Apprentices. Membership of NUS grew during Ben's time here and he used his wide network of contacts within civil society to broaden the reach and message of NUS and place it in a strong position in the run up to the general election.
"The organisation is grateful for Ben’s contribution and would like to take this opportunity to thank him and to wish him every success in the future."