This trial is designed to investigate the use of a double unit umbilical cord blood infusion in patients with life threatening haematological malignancy but no suitable donor available. The study is being jointly conducted by the Australasian Leukaemia and Lymphoma Group and Amgen Australia. The trial aims to assess whether two units of donated cord blood would improve the engraftment rates as this remains low when only one unit is used. All participants will be monitored for complications and assessed for changes in their clinical condition. According to the information posted on the ANZCTR registry, the trial has not yet commenced.