I think there should be a standard immigration test that MUST be passed before you even enter the country.
The test should be,
"Do you swear to place your allegiance to the UK before any allegiance to any deity or religious leader, this includes Mohammed, Allah, Jesus, Jehovah, and the Buddha?"
I should think the correct answer to both of those questions is a bit obvious, even if they are designed to be needlessly informative for the sake of making people swear that the UK is more important than Allah.
There should be a simple rule. If you want to live in the UK, live by UK law. No forced marriages, no honour killings, no segregation and oppression of women - you will integrate with British society, you will take on British values, and you will not unduly criticize the British way of life.
I'm not saying that no one should ever be allowed to criticize the government - I'm saying if they advocate violence against the government or the citizens, they will (if they are immigrants) be charged, and if found guilty, immediately deported and never allowed to even visit the UK again, and placed on a Terror Watch, or (if native) tried and possibly imprisoned for 10-20 years (since it could be classed as treason or conspiracy to incite hatred and violence, I see those as serious crimes).
Oh by 10-20 years I dont mean let out after 6 months for good behaviour. I mean 20 years, if you are shown to have reformed yourself, you may be let out after an absolute minimum of 10, but placed on probation.