Those subjects randomised to the tight control arm will be reviewed every 4 weeks (by the PI at each site or a designated researcher), and will be treated according to a rapidly escalating regime, involving standard DMARDs and biologics. Initial therapy will be with oral methotrexate, increasing in dose rapidly over the first 8 weeks of the study. From the 12 week visit onwards, escalation of therapy in this arm will be performed if subjects do not meet the objective target of Minimal Disease Activity. Initial escalation will be to combination DMARD therapy. If patients in the tight control arm fail to meet the MDA criteria and fulfil the NICE criteria for the use of TNF blockers in psoriatic arthritis at 24 weeks, then they will be offered treatment with these medications. Therapy will continue to be modified throughout the 48 week follow-up until a state of minimal disease activity is reached. The control group will be seen every 12 weeks in a general rheumatology clinic and will receive standard care, involving standard DMARDs and biologics as appropriate. Treatment will be prescribed as felt appropriate by the treating physicians with no set protocol and no restrictions.