Work permits, which will soon become ‘certificates of sponsorship’, will be replaced by Tier 2. All applicants in these tiers will be expected to have a sponsor such as a college institution or an employer, with the exception of the already implemented Tier 1.     These sponsors will be registered with the UK Border Agency and will require a licence to do so. Tiers 3 and 4 are expected to be carried out by the end of 2009 at the latest. For details of the various work categories see below: