Patients who survive a stroke are often left with an arm that cannot be used. One reason for this is that the muscles affected by the stroke become overactive. This is known as spasticity. Such unwanted muscle overactivity, if left untreated or poorly managed, can lead to limb deformities. For example, the wrist and fingers in the arm affected by spasticity become stiff and curl into a fist and the hand cannot be used for any functional purpose. Palm hygiene can become difficult and patients find this deformity unsightly and painful. Botulinum toxin (BT) has been shown to reduce muscle overactivity and is licensed for this purpose. In current practice this treatment is often used as a last line of defence. Although BT can reduce the muscle overactivity, when injected using current protocols, it seems to have little impact on the recovery of function and/or treating the limb deformities and pain. If BT can be given in the early stages of a stroke, i.e. as soon as the muscle overactivity is observed, then we will be able to treat spasticity and may prevent the limb deformities and pain from developing. We may also be able to assist the recovery of arm movement in some of the patients who would otherwise not have regained this. In addition to benefiting the patient, the prevention of secondary complications by early treatment may reduce the costs of long term care to the NHS . We hope to discover if our plan of providing early treatment with BT is more effective than the current approach. If we demonstrate that the treatment is effective we will be able to introduce this new method almost immediately within the NHS through our collaboration with doctors and therapists who are actively treating patients with this condition.