Britain and terrorism

Argue, using academic sources, how much of a threat isis poses to the UK?

Readings include:
hewitt 2008 british war on terror: terrorism and counter terrorism on the home front since 9/11
Philipps 2006 londonistan
Cockburn 2015 the rise of the islamic state
Wilkinson 2007 homeland security in the UK

Journals include:
Behavioural sciences in terrorism and political aggression
Studies in conflict and terrorism
Terrorism and political violence
Critical terrorism studies

Newspapers include:
The times
Daily telegraph
New York times
Washington post