It's an old debate, much depending on definition: the narrower one's definitions (being inevitably drawn from feudalism's most developed forms), the less "feudal" late Saxon England becomes. Taken to extremes it can boil down to "how late 12th-century was early 11th-century England?" And the answer is of course "Not much", but that wasn't really the question.

Setting aside the broader conception of feudalism as a top-to-bottom socio-economic formation, the greatest advocate of 11th-century continuity remains FW Maitland:

If now we look at that English state which is the outcome of a purely English history, we see that it has already taken a pyramidal or conical shape. It is a society of lords and men. At its base are the cultivators of the soil, at its apex is the king. This cone is as yet but low. Even at the end of William's reign the peasant seldom had more than two lords between him and the king, but already in the Confessor's reign he might well have three. Also the cone is obtuse: the angle at its apex will grow acuter under Norman rulers.

Writing eighty years later of law and administration, Sawyer echoed Maitland in concluding that:

Some changes of detail were, of course, inevitable after such a violent seizure of power and the displacement of the English elite, bit the continuity is more significant than the change. It has been well summed up by Frank Barlow: "On the whole it seems that William's monarchy was Edward's run at full power". The machinery of English government was therefore preserved but the personnel, especially in positions of great reponsibility, was changed.

While noting that "it is doubtful if the proportion of continuity and discontinuity of landholding structures can ever be weighed accurately given the data we have", Harvey suggests that even elements of William’s great survey derived from pre-Conquest returns:

Within Domesday itself survive lists for Yorkshire, previously thought of as summaries of Domesday. One section dealing with royal lands is arranged under landholders of the 1060s (including Earl Tostig, who died in 1065) and another section is arranged by "wapentakes" with the holders of land annotated in. Such fiscal lists emphasise the force of the Anglo -Saxon foundations of Domesday Book. They also show that the great landholders knew their fiscal responsibility before, as well as after, the Conquest.

Others of course argue forcefully that it was far more revolution than evolution and that the differences were such as to disqualify Saxon England from use of the f-word.

One long-running criticism of the continuity claim has revolved around the suggested absence of an explicitly contractual element in Saxon noble tenure (see the engaging early review by Adams): the king retained direct authority over all, unlike feudalism's hierarchy of loyalties and jurisdictions - yet even Stubbs, who saw Saxon institutions as thus "Germanic" rather than feudal pointed to William's own extraction of a personal pledge from the great landowners - others' vassals as well as his own - as no less "anti-feudal"(!).