Inclusion Criteria:  Participant is willing and able to give informed consent for participation in the study. Male or Female, aged 18+ years. Diagnosed with histologically or radiologically diagnosed colorectal adenocarcinoma. Anaemic at point of diagnosis of colorectal adenocarcinoma (Defined as haemoglobin 10g/L below WHO criteria: 120g/L for males and 110g/L for females, to account for a 10% fluctuation in Hb) Undergoing surgery for colorectal cancer with curative intent. Date of planned surgery is ≥ 14 days from date of planned initiation of recruitment. Able (in the investigators opinion) and willing to comply with all study requirements. Willing to allow his or her General Practitioner and consultant, if appropriate, to be notified of participation in the study.  Exclusion Criteria:  Patients who do not have a histological diagnosis of colorectal adenocarcinoma Female participants who are pregnant, lactating or planning a pregnancy during the course of the study. Patients with evidence of iron overload or disturbances in utilisation of iron as stated in the product SPC. Previous gastric, small bowel or colorectal surgery (where ≥50% of stomach or terminal ileum has been resected) Chemotherapeutic treatment within the last 4 weeks. Known previous anaemia not attributable to colorectal carcinoma (i.e. anaemia in patients with well established, inflammatory disorders) Known haematological disease. Features necessitating urgent surgery (e.g. obstructive symptoms). Previous allergy to intravenous or oral iron or related iron products. Patients who are unable to consent. Any other significant disease or disorder which, in the opinion of the Investigator, may either put the participants at risk because of participation in the study, or may influence the result of the study, or the participant's ability to participate in the study. Participants who have participated in another research study involving an investigational product in the past 12 weeks Confirmed liver or lung metastases