1. Just because a book is controversial doesnt mean it is wrong.
2. Why should the book and the author be not reputable and biased?
3. Britain was nothing more than a charlatan in WW2, a dwarf pretending to be a giant. If Germany executes Raeders Mediterranean strategy and conquers the med in 1941, it is hard to see how Churchill could have remained in office and how the country would have remained in the war - even with American help.