isn't immigration self-limiting?

[rogueantimatter]

If there was immigration to the extent that everywhere was built-up and quality of life was deceased wouldn't people move away and/or stop moving to Britain?

Oops. 'quality of life was decreased.

I imagine so, but how bad would it have to get for that to happen?

How long do you think it would take for the uk to be worse than a refugee camp in Syria, for example?

The people in refugee camps are trapped.

That's an example of the situations that people are leaving - they are in most cases, extreme, they've been bombed, starved, persecuted and seen family members killed or 'disappear'

How long before the U.K. seems to be less attractive than that?

It's not only about how attractive a country is, but how unattractive the countries or origin are and other destination countries are.

One of the benefits of international development and supporting developing countries is that people from there will be less likely to want to leave. Same with peace vs war, and nasty regimens.

When the UK will soon be paying £9.20 per hour minimum wage, and the minimum wage in Bulgaria is only £6.87 a day then migrants will continue to migrate from the poorer parts of the EU to the UK.

As for immigration being self-limiting, the EU is like any empire, it must expand. No empire ever says - "I'm big enough now, I'll stop growing'.
It will expand to include countries that are already being readied to join - Albana, Macedonia, Bosna, Monetnegro, Serbia - very poor countries whose populations will seize the opportunity to get higher wages abriad.

Then there is the prospect of 75million population Turkey joining and Ukraine and possibly Georgia.

In 2018 4.29 million Croatians will have the right to come and live and work in the UK.

At some point the UK has to decide whether to build up to accommodate these extra workers or to leave the free movement agreement.

The danger also arises when you have a very large population that you may not be able to import all the food and fuel you will need to sustain such a large population. It may be OK in times of peace, but industrial action or conflict could quickly lead to civil unrest when a very large population has no reserves.

And there is also the danger of conflict with other powers, such as Russia, as the EU seeks to groom former Soviet countries into joining the EU - like Ukraine.