The news follows reports in May that CYBG would make 150 senior staff redundant to trim costs, following a 60 per cent slump in bottom-line profits compared with last year.
It was CYBG’s first set of results following its demerger from National Australia Bank in February.
Gardner left the company last week, CYBG confirmed to PRWeek on Thursday. A spokesman declined to give further details.
He has 20 years of experience in corporate comms and was head of external affairs for National Australia Banking Group for four years and head of external affairs for National Australia Group Europe for three years, before his job at CYBG.
Gardner – who was responsible for the reputation of CYBG and its brands – won a CIPR Award in 2016 for his work in support of the demerger and subsequent IPO.
The group had more than 250 retail branches, nearly 7,300 staff and income of £492m in the six months to 31 March 2016, its accounts show.
Gardner previously worked for HBOS as its PR director for five years and as a senior press officer for the insurance firm General Accident, following a stint as a journalist on the Dundee Courier early in his career.
He is also trustee at the charity the Scottish Association for Mental Health, a position he has held for three years.