I suppose it was only a matter of time: Migrants moving up through Europe, having successfully negotiated the Mediterranean or Aegean Seas, or the land route through Eastern Europe, arrive at the northern shore of the continent and then set their sights on crossing the next body of water to penetrate the British Isles.
And why not? After all, at its widest, only about 150 miles separate the United Kingdom (UK) from the continent; at its narrowest, it is just a hair wider than 20 miles — thus the French name for the channel: La Manche ("the Sleeve").
In this regard, British newspapers are reporting two things:
First, that a group of 18 smuggled Albanians were rescued in the Channel by the Royal Navy, and that a couple of British men have been charged with attempting to smuggle them;
Second, that the UK is much more vulnerable to alien smuggling breaches than generally believed and that until recently British officialdom (having sent a goodly portion of its limited maritime resources to help the EU with its Med/Aegean crisis) has been wont to disregard the problem despite warnings from Border Force inspectors (see here and here).
Although these interdicted migrants were Eastern Europeans, and not Syrians, Iraqis, or others who have made the "crisis" trek, it would be foolish to believe anything except that once intended migrants from anywhere start plying the waters of the Channel and pointing the way northward literally and figuratively to others, the floodgates will open. The effectiveness of Britain's response then will depend heavily on two factors: the will to react quickly and appropriately, and the capacity to do so.
As to the capacity: British leaders such as Prime Minister David Cameron, who have invested their political chits in persuading voters to remain in the European Union in this month's referendum, are scrambling to bolster the undermanned and shaky cadre of anti-smuggling officers and vessels, lest this exposure of vulnerability tilt the vote toward "Brexit" (the nickname for Britain's exit from the EU). Border Forces are being given new arrest powers, and new patrol boats are under construction.
As to reacting quickly and appropriately? That remains to be seen. If Britain makes the EU's mistake and engages in migrant "rescue and resettlement" as if the two concepts are a package deal, they will quickly lose control. Effective border controls inevitably rest on the principle of removal and repatriation for all but legitimate refugees. Being able to intelligently distinguish them from the masses becomes the bright line test that many nations fail.