The EU needs a common immigration policy
Immigration is a controversial topic all over Europe, not just in Britain. Different member states are affected to differing extents. Inevitably the countries at the borders of the union bear the brunt of the immigration flows and the costs of patrols, detention and deportation. The burden therefore needs to be better shared, but should countries like Britain pay more when we are such a long distance from the borders of Europe.
Since laws,cultures,ideals,dominant religions and languages vary, so should immigration policies.
To protect western values
Europe has to toughen up and be united against people-smugglers who traffic illegal immigrants and sex-workers in and out of Europe.
'Freedom of speech/expression' is held very high in this Zeitgeist's understanding of western values. Europe has to make sure that intolerance,hatred and violence/aggression in answer to free speech, is curtailed then snuffed.[[http://www.bbc.co.uk/blogs/thereporters/gavinhewitt/]]
Britain does bear the brunt of immigration
No not immigrants, their progeny 'British' Born and Bred, You can not call people born and bred in the U.K immigrants, maybe ghetto-dwellers, racial-minorities but not immigrants. The parents of certain British terrorists 'were' immigrants and suffice to say the parents were never involved in any terrorist activity.
Spain, however WAS attacked by immigrants or F.O.B s if you like.Restricting immigration in Spain could curtail terrorism, since their terrorists weren't home-grown. However, since having a British passport, means easy access to all of Europe,it makes sense therefore,for all of Europe to have a common immigration policy.
It already controls our borders?
The mass immigration element of 'subversion' :
It should also be noted that the rest of Europe is as concerned about immigration as Britain is. Catching more at Europe's borders is better than waiting for them to reach the Channel.