Im a bit intrigued,if we're all under an EU banner, as to why people who made it to Europe see the UK as the final destination, when our powers that be are doing their best to refuse entry and in effect leave the problem in France. Buggered if I can get my head around that. We have no money to cope with an influx, let alone our own, so who is selling the idea its a land of plenty.
I broadly agree with most of the posts here. However I quoted this above because it asks a couple of questions.
Firstly you ask why migrants see the UK as last port of call, well I expect not all do, but those that do there is an elephant in the room that being a bit left of centre as a board no one has mentioned (except to have a dig at the Lords which I agree with). And that is we do have a working economy like it or not, we do not have genocide, we do have a welfare system and we do have a free NHS at the point of need. Most countries certainly do not have these, so for all our moaning at our lives we do need to remember this.

I've travelled a lot, mainly for work, and I can say that the view that we have generous benefits or indeed benefits at all is something others DO view about us. Now before Master R accuses me of being Richard Littlejohn, I am not for one moment saying migrants do not come here and work, because most do.
Don't take my word for it though about how we are seen, let the Mayor of Calais, Natacha Bouchart say it. She said "Britain was an ‘El Dorado’ for thousands of migrants flocking to Calais because of generous state handouts. They want to go to England because they can expect better conditions on arrival there than anywhere else in Europe or even internationally."
As for why people come here there must be a thousand reasons; to find work, to build a better life, to make use of the welfare, to free persecution....who knows. While I love the influx of influences into this country, we do have finite space. And I also get fed up of reading right wing papers going on about migrants coming to live off welfare, and left wing papers accusing anyone with an opinion as racist.
And in answer to the second question in the quote, we do indeed have money in this country, we are one of the wealthiest on the planet.