Currently in the United Kingdom (UK), either chemotherapy alone or chemotherapy followed by CRT can be used in the management of inoperable pancreatic cancer that has not spread. CRT consists of 25-30 radiotherapy treatments in combination with chemotherapy. Although this treatment is effective in controlling local symptoms and slowing down the pace of cancer, in most cases it is unable to shrink it enough to make it operable. Some of the reasons for this could be the lack of oxygen and lack of blood flow within the tumour making it resistant to the effects of CRT. This study will investigate whether increasing the dose of radiotherapy, or increasing the oxygen and blood supply to the tumour by giving nelfinavir, or a combination of both, can improve outcomes. We also want to know what the additional toxicities from such intensive approaches are.