The port said extra checks would be suspended, after travellers faced queues as temperatures soared.
Amber heat health alerts are in place for the Midlands, eastern and south-east England.
Reforms are needed of the welfare system to tackle the high numbers of young people not in work or education, says Alan Milburn.
The party says its proposed policy would cost £5bn a year and could be paid for through cuts to welfare.
The three teenagers were not given custodial sentences for their roles in the rape of two girls.