 This is a phase II trial to assess whether IRESSATM gefitinib has anti-tumour efficacy in patients with breast cancer. The trial proposes to enter 27 patients who have acquired resistance to tamoxifen and 27 patients with ER negative tumours. However for each of these two types of patients recruitment will stop after 14 patients have been entered in order to confirm that IRESSATM gefitinibhas anti-tumour efficacy. If no patient out of 14 in a group has shown clinical benefit ie an objective response CR or PR or stable disease SD for at least 24 weeks then a clinical benefit rate of 20 can be ruled out with 95 certainty. If one or more of the objective response or stable disease 24 weeks has been seen in the first 14 patients recruited in a group then recruitment to that group will recommence to a total of 27 patients. If 14 patients are entered into an arm but not all 14 patients are available for final analysis and the toxicitysafety and tolerability profile of the therapy is acceptable and documented and a clinical benefit is seen in the patients, enrolment of additional patients beyond the initial 14 may be made based on overall clinical assessment. 