Muslim imams are being fussy on the eve of the referendum on the EU membership of the UK, and have already issued a fetwa calling Muslims to migrate into Great Britain while the country is staying a EU member and such an opportunity is available for them.
After the withdrawal, all the existing loopholes so far ensured by the Brussels legislature will be blocked. London is to establish its full control over the state borders making it impossible for anybody from the EU to enter Great Britain without the thorough checkup. Fully fledged citizens, legal immigrants or terrorists acting under the cover of refugees, all of them will be subject to this procedure.
This is how it's going to be after the 23rd of June. What is important presently is to estimate how many thousands of Muslims will manage to resettle in the United Kingdom before the referendum takes place, and how many of those ones will be terrorists actually.