Inclusion Criteria:

        - 1) Written informed consent obtained from the patient prior to performing any
        protocol-related procedures, including screening evaluations.

        2) Age > 18 years at time of study entry. 3) Must have a life expectancy of at least 12
        weeks 4) Eastern Cooperative Oncology Group (ECOG)performance status of 0 or 1. 5) Body
        weight >30kg. 6) Biopsy-proven, newly diagnosed primary rectal adenocarcinoma, with the
        lowest part of the tumour less than 12 cm from the anal verge using a rigid rectoscope or
        flexible endoscope.

        7) Mandatory tumour and blood samples for translational research. 8) High risk MRI-defined
        rectal cancer: Presence of at least 1 of the following on high resolution, thin-slice MRI
        (3 mm): Upper-Middle Third Tumours

        -mrT3

          1. Extramural vascular invasion (EMVI) positive

          2. Extramural extension > 5 mms into perirectal fat

          3. Mesorectal fascia (MRF) threatened or involved (tumour or lymph node < 1mm from MRF)
             -mrT4 Distal Third Tumours (≤5 cm from anal verge) - mrT3 tumour at or below levators
             - T4 as above N2(≥4 lymph nodes at mesorectum radiologically suggestive of metastatic
             lymph nodes) 9) No contraindications to chemotherapy and radiotherapy 10) Adequate
             normal organ and marrow function as defined below:

             - Haemoglobin ≥9.0 g/dL.

             - Absolute neutrophil count (ANC) >1500 per mm3.

             - Platelet count ≥100,000 per mm3.

               -  Serum bilirubin ≤1.5 x institutional upper limit of normal (ULN). This will not
                  apply to patients with confirmed Gilbert's syndrome (persistent or recurrent
                  hyperbilirubinemia that is predominantly unconjugated in the absence of hemolysis
                  or hepatic pathology), who will be allowed only in consultation with their
                  physician.

               -  AST (SGOT)/ALT (SGPT) ≤2.5 x institutional upper limit of normal.

               -  Measured creatinine clearance (CL) >40 mL/min or Calculated creatinine CL>40
                  mL/min by the Cockcroft-Gault formula (Cockcroft and Gault 1976) or by 24-hour
                  urine collection for determination of creatinine clearance:

             Males:

             Creatinine CL (mL/min) = Weight (kg) x (140 - Age) 72 x serum creatinine (mg/dL)

             Females:

             Creatinine CL (mL/min) = Weight (kg) x (140 - Age) x 0.85 72 x serum creatinine
             (mg/dL) 11) Evidence of post-menopausal status or negative urinary or serum pregnancy
             test for female pre-menopausal patients. Women will be considered post-menopausal if
             they have been amenorrheic for 12 months without an alternative medical cause. The
             following age-specific requirements apply:

             - Women <50 years of age would be considered post-menopausal if they have been
             amenorrheic for 12 months or more following cessation of exogenous hormonal treatments
             and if they have luteinizing hormone and follicle-stimulating hormone levels in the
             post-menopausal range for the institution or underwent surgical sterilization
             (bilateral oophorectomy or hysterectomy).

               -  Women ≥50 years of age would be considered post-menopausal if they have been
                  amenorrheic for 12 months or more following cessation of all exogenous hormonal
                  treatments, had radiation-induced menopause with last menses >1 year ago, had
                  chemotherapy-induced menopause with last menses >1 year ago, or underwent
                  surgical sterilization (bilateral oophorectomy, bilateral salpingectomy or
                  hysterectomy).

                  12) Patients willing and able to comply with the protocol for the duration of the
                  study including undergoing treatment and scheduled visits and examinations
                  including follow up.

             Exclusion Criteria:

               -  1) Participation in another clinical study with an investigational product during
                  the last 6 months.

                  2) Concurrent enrolment in another clinical study, unless it is an observational
                  (non-interventional) clinical study or during the follow-up period of an
                  interventional study.

                  3) Prior therapy for rectal cancer. 4) Presence of metastatic disease or
                  recurrent rectal tumour. Familial Adenomatosis Polyposis coli (FAP), Hereditary
                  Non-Polyposis Colorectal Cancer (HNPCC), active Crohn's disease or active
                  ulcerative Colitis.

                  5) Extensive growth into cranial part of the sacrum (above S3) or the lumbosacral
                  nerve roots indicating that surgery will never be possible even if substantial
                  tumour down-sizing is seen.

                  6) Known DPD deficiency. 7) Persistent peripheral neural toxicity > grade 2. 8)
                  Intestinal occlusion. Patients with intestinal occlusion due to the primary
                  rectal tumour, that could participate in the study, may be included after a
                  derivative intestinal surgery.

                  9) Any previous treatment with a PD1 or PD-L1 inhibitor, including durvalumab.
                  10) Mean QT interval corrected for heart rate (QTc) ≥470 ms calculated from 3
                  electrocardiograms (ECGs) using Fridericia's Correction.

                  11) Current or prior use of immunosuppressive medication within 28 days before
                  the first dose of durvalumab, with the exceptions of intranasal and inhaled
                  corticosteroids or systemic corticosteroids at physiological doses, which are not
                  to exceed 10 mg/day of prednisone, or an equivalent corticosteroid. The following
                  are exceptions to this criterion:

               -  Intranasal, inhaled, topical steroids, or local steroid injections (e.g., intra
                  articular injection).

               -  Systemic corticosteroids at physiologic doses not to exceed 10 mg/day of
                  prednisone or its equivalent.

               -  Steroids as premedication for hypersensitivity reactions (e.g.,CT scan
                  premedication).

                  12) Any unresolved toxicity NCI CTCAE Grade ≥2 from previous anticancer therapy
                  with the exception of alopecia, vitiligo, and the laboratory values defined in
                  the inclusion criteria

               -  Patients with Grade ≥2 neuropathy will be evaluated on a case-by-case basis after
                  consultation with the Study Physician.

               -  Patients with irreversible toxicity not reasonably expected to be exacerbated by
                  treatment with durvalumab may be included only after consultation with the Study
                  Physician.

                  13) Any concurrent chemotherapy, IP, biologic, or hormonal therapy for cancer
                  treatment. Concurrent use of hormonal therapy for non-cancer-related conditions
                  (e.g., hormone replacement therapy) is acceptable.

                  14) Previous radiotherapy in the pelvic region (e.g. prostate) or previous rectal
                  surgery (e.g.TEM).

                  15) History of allogenic organ transplantation. 16) Active or prior documented
                  autoimmune or inflammatory disorders (including inflammatory bowel disease [e.g.,
                  colitis or Crohn's disease], diverticulitis [with the exception of
                  diverticulosis], systemic lupus erythematosus, Sarcoidosis syndrome, or Wegener
                  syndrome [granulomatosis with polyangiitis, Graves' disease, rheumatoid
                  arthritis, hypophysitis, uveitis, etc]). The following are exceptions to this
                  criterion:

               -  Patients with vitiligo or alopecia

               -  Patients with hypothyroidism (e.g., following Hashimoto syndrome) stable on
                  hormone replacement

               -  Any chronic skin condition that does not require systemic therapy

               -  Patients without active disease in the last 5 years may be included but only
                  after consultation with the study physician

               -  Patients with celiac disease controlled by diet alone 17) Uncontrolled
                  intercurrent illness, including but not limited to, ongoing or active infection,
                  symptomatic congestive heart failure, uncontrolled hypertension, unstable angina
                  pectoris, cardiac arrhythmia, interstitial lung disease, serious chronic
                  gastrointestinal conditions associated with diarrhea, or psychiatric
                  illness/social situations that would limit compliance with study requirement,
                  substantially increase risk of incurring AEs or compromise the ability of the
                  patient to give written informed consent 18) History of another primary
                  malignancy except for

               -  Malignancy treated with curative intent and with no known active disease ≥5 years
                  before the first dose of IP and of low potential risk for recurrence

               -  Adequately treated non-melanoma skin cancer or lentigomaligna without evidence of
                  disease

               -  Adequately treated carcinoma in situ without evidence of disease 19) History of
                  active primary immunodeficiency 20) Active infection including tuberculosis
                  (clinical evaluation that includes clinical history, physical examination and
                  radiographic findings, and TB testing in line with local practice), hepatitis B
                  (known positive HBV surface antigen (HBsAg) result), hepatitis C, or human
                  immunodeficiency virus (positive HIV 1/2 antibodies). Patients with a past or
                  resolved HBV infection (defined as the presence of hepatitis B core antibody
                  [anti-HBc] and absence of HBsAg) are eligible. Patients positive for hepatitis C
                  (HCV) antibody are eligible only if polymerase chain reaction is negative for HCV
                  RNA.

                  21) Receipt of live attenuated vaccine within 30 days prior to the first dose of
                  IP. Note: Patients, if enrolled, should not receive live vaccine whilst receiving
                  IP and up to 30 days after the last dose of IP.

                  22) Female patients who are pregnant or breastfeeding or male or female patients
                  of reproductive potential who are not willing to employ effective birth control
                  from screening to 180 days after the last dose of durvalumab monotherapy.

                  23) Known allergy or hypersensitivity to any of the study drugs or any of the
                  study drug excipients.

                  24) Judgment by the investigator that the patient is unsuitable to participate in
                  the study and the patient is unlikely to comply with study procedures,
                  restrictions and requirements.

                  25) Known allergy or hypersensitivity to IP or any excipient