The homelessness charity St Mungo’s is looking into an allegation by the trade union Unite that one of its officers was "victimised" by the charity’s staff.
The charity has been locked in a dispute with the trade union over alleged changes to staffing and terms and conditions at the charity, with a strike ballot due to start today.
The charity has consistently denied Unite’s claims about staffing and employee terms and conditions.
The victimisation allegations by Unite centre on emails it obtained under a subject access request, in which the union claimed that its lead trade representative, Aftaar Malik, was referred to as a "martyr".
The union said the email came after a meeting at which Malik was "aggressively" asked to leave a managers’ forum meeting and left feeling "humiliated".
A statement from St Mungo’s said the charity was looking into the trade union’s complaint.
"We’ve received an allegation of victimisation from a Unite official," the statement said.
"As a charity, we take any complaint seriously and have begun an investigation into this."
Tabusam Ahmed, regional officer for Unite, said: "Unite is profoundly concerned about the way St Mungo’s appears to be victimising a lead trade union representative. Threatening to make a ‘martyr’ of a union rep is totally unacceptable and will not be tolerated.
"Any attempts to victimise our representatives or stop them from speaking up for members and carrying out legitimate trade union activities will be met with the full force of our union."
The union said it believed the treatment of Malik was "part of a bid to undermine our union reps ahead of the strike ballot".
The Charity Commission has said that it is examining information it has received about the staffing and pay and conditions dispute between St Mungo’s and Unite, and is "assessing the situation".