‘Part 3 of the Immigration Bill gives a host of new, wide powers to immigration officers.
A person with leave to enter arrives in at the airport. Schedule 19(1) and (2) – the first section of Part 3 – gives immigration officers the power to curtail leave, rather to simply determine whether leave has been given and act accordingly. So someone arriving in the UK even with the appropriate leave will now have a lingering uncertainty as to whether they will be allowed in. This is likely to affect few migrants, but is indicative of the greater powers given to immigration officers throughout the Bill.’
Free Movement, 1st October 2015
Source: www.freemovement.org.uk