Unison is the second largest trade union in the United Kingdom.
Maureen Marinel will be the first lesbian elected as vice-president.
"Throughout my life, fairness has always been key. Unison is not a banging on the table type of union – we want to find a fair and reasonable solution that is best for everyone" she said.
"This is a guiding principle that will take me through my presidential term, as I help the union, and public services, face head on some of the biggest challenges that we have faced in my lifetime."