It’s not entirely down to the EU, OG. In fact, far from it.
In 2015 around 635,000 people (those who we know about, that is) arrived to settle here. Of those 265,000 were citizens of other EU nations whilst 286,000 were citizens of countries outside the EU. (The remaining 84,000 were UK citizens returning from abroad). So of the foreign nationals entering the UK only 48% were from other EU countries.
I accept that the UK as no control over immigration by citizens of other EU countries (though, of course, most will know that I don’t exactly agree with it!). But it does have control over who enters from elsewhere and it seems it is perfectly happy to allow as much immigration from outside the EU as it has to accept from within. China (17%) India (16%) and the USA (7%) accounted for 40% of that total and it could well be that, from those countries at least, skilled or professional people with something to offer were being allowed to settle here. They, of course, are needed to fill vacancies because this country has a skills shortage caused by poor education and youngsters being ill-equipped for work. But for every one of them there is at least one from the EU who, more likely than not, is either low skilled or unskilled and who, if they secure any employment at all, probably take jobs which some of the 2m people already here without work could do but won’t. Without this the imigration situation would look far less alarming.
The whole issue of immigration is a complete and utter mess. We have to allow in people who have little to offer the UK, will probably not secure employment but even if they do will require considerable support in having their wages “topped up” (for which you can read, in many cases, doubled) by Tax Credits. Many of them earn nothing at all and end up kipping in the subways under Marble Arch. Meanwhile those from other countries who have skills and will probably be high earners have to jump through hoops to be allowed to settle here and contribute.
“We are in the EU and have signed up to abide by their membership rules, these rules include open movement and a % of outside immigration”
Leaving aside the current refugee crisis (where EU leaders are trying – mainly unsuccessfully – to “distribute" illegal immigrants around the EU) there is no stipulation under EU rules to say that migration from outside the EU must be sustained at any particular level.
“Now would you suggest that we leave the EU immediately and therefore lose the benefits that we have from being in the EU?”
Yes, absolutely. See many of my answers to find out why I believe this and also to see some comment on the alleged "advantages" (of which the above is just one of many) of our EU membership.