Of course.

Excerpt:

The survey found almost half (46 per cent) of offenders had their origins in south Asia including 28 per cent who had Pakistani heritage - of whom at least 80 per cent were British nationals.
Six of the eight major plots in Britain, 75 per cent, contained individual members who had trained in Pakistan and four of the leaders of those plots were directly linked to one or more Pakistani based terrorist groups.


Even if 10% of the Islamists could be deported it would make a big difference.