You have been asked to see an in-patient on the stroke ward by one of the nurses as she is concerned about an ulcer on the patient’s leg. On examination, you note the presence of a large ulcer on the inner part of the left ankle, peripheral oedema and various veins on the affected leg and hyperpigmentation in the skin around the ulcer. The patient also informs you that the mild pain she has is relieved when the nurses lift her leg up. What is the most likely diagnosis?