A number of senior Labour Party staff have resigned ahead of the expected appointment of Jennie Formby as general secretary on Tuesday.
Among those leaving are director of governance John Stolliday and director of policy and research Simon Jackson.
They are the latest in a string of departures from Labour's headquarters.
The National Executive Committee will choose the new general secretary, with Ms Formby, a Unite official, up against former NUT leader Christine Blower.
Ms Formby, a former political secretary at Unite – Labour's largest financial backer – has the support of Jeremy Corbyn and other senior figures in the party.
If she wins, she is expected to begin a shake-up of Labour's organisational and campaigning activities.
In an e-mail to staff announcing his departure, Mr Stolliday said he was "honoured" to have worked under four party leaders – "including two prime ministers" and acknowledged that his unit, which includes the compliance department "collectively deal with some of the most difficult issues in the organisation".
Others leaving the party's headquarters include Dan Simpson, acting parliamentary Labour Party secretary, Neil Fleming, acting London regional director and Julie Lawrence and Tracey Allen – both of whom worked in the general secretary's office under Iain McNicol – who left his post last month.
Emilie Oldknow, the party's executive director for governance, membership and party services' had already said that she would be departing in the summer. The party's executive director of elections, organisations and campaigns Patrick Heneghan, resigned last autumn.