Despite all the chaff and flare from the Mayor/Marie of Calais, it is perfectly acceptable for the UK to safeguard their borders - the exact reason for the opt out on Schengen. The French obviously understand this as they recently closed the border with Italy over migration concerns.
This will continue whilst Europe cannot control their borders and the Med is a 6 lane highway for economic migrants. Easy to be critical of the Italians & Greeks but their maritime resources are swamped.