Sue Page, Chief Executive of the trust, said: “We are heartbroken at the loss of a member of our South Tees’ family.
“Mark had worked for the trust for 20 years and was a kind and brilliant colleague who will be missed by everyone.
“Our heartfelt condolences are with Mark’s partner Amanda and their family at this incredibly sad and difficult time.
“We have been in contact with Amanda to pass on our condolences and offer all our support.
“We ask that you please respect their privacy during this time.”