Historically, waits for assessment in A&E were very long in some areas of the UK. In October 2002, the Department of Health introduced a four-hour target in emergency departments that required departments in England to assess and treat patients within four hours of arrival, with referral and assessment by other departments if deemed necessary. It was expected that the patients would have physically left the department within the four hours. Present policy is that 95% of all patient cases do not "breach" this four-hour wait. The busiest departments in the UK outside London include University Hospital of Wales in Cardiff, The North Wales Regional Hospital in Wrexham, the Royal Infirmary of Edinburgh and Queen Alexandra Hospital in Portsmouth.