A spokesman at Brocade confirmed the departures but was unable to offer any other meaningful details at the time of going to press.
"Both have decided to leave Brocade to pursue opportunities outside of the company. We wish them well for the future, and thank them for their contribution over the years," he told MicroScope.
Giddins (pictured) was handed the role of EMEA partner boss in April 2009 after jumping ship from Nortel, where she was pan-European channel leader, and had also managed distribution across EMEA.
Phillips, who joined Brocade in January 2002 as UK country manager - and doubled up as regional sales director in the last 18 months - said on his LinkedIn profile that he is looking for a new opportunity.
The Brocade spokesman added: "We are actively recruiting and aim to fill these positions as soon as possible."
The exact reason for the abrupt departures is not clear but sources close to the situation claimed that financial expectations had not been met.
Giddins and Phillips were unavailable for comment.