A first in man study of autologous culture expanded MSC cell therapy for the Achilles tendon. This study is a phase II, single centre, proof of concept study using an Advanced Therapy Investigational Medicinal Product (ATIMP). The ATIMP is between 4-20 x 106 autologous bone marrow derived culture expanded mesenchymal stem cells. The study has been reviewed by the MHRA, is fully ethics approved (Ethics approval granted 23/12/13. REC reference - 13/LO/1670), and is registered on the Clinical Trials database (ClinicalTrials.gov Identifier: NCT02064062).