Londonistan: How Britain is Creating a Terror State Within is a 2006 best-selling[1] book by the British journalist Melanie Phillips about the spread of Islamism in the United Kingdom over the previous twenty years.

Both see Britain as "a debauched and disorderly culture of instant gratification, with disintegrating families, feral children and violence, squalor and vulgarity on the streets".

[2] Describing the book in The American Conservative magazine, the writer Theodore Dalrymple wrote "the British journalist Melanie Phillips documents not only the establishment and growth of Muslim extremist groups in London but the administrative incompetence and cultural weakness that permitted it to happen.

"[3] Writing for The Daily Telegraph, the historian and writer Michael Burleigh decided that the book could not be more "timely" and praised her "sensible suggestions".

[5] Phillips has been noted to have praised the scholarship of Bat Ye'or, and Londonistan has been described by Christopher Othen as "her own book about the localised version of Eurabian dhimmitude all around her".