Why do maritime patrol aircraft still need long range?

If Britain and Norway cooperate, why do their maritime patrol aircraft still need long range?

Because suitable bases are limited and the aircraft need endurance to search wide patrol patterns at fuel-hungry low altitude, not merely fly a straight route out and back.

The answer separates ferry range from useful patrol endurance. Large maritime patrol aircraft can operate only from a limited number of suitable British and Norwegian airfields. Their crews must fly broad, repeated search patterns rather than travel directly to one point and return. Low-altitude work also increases fuel consumption, so long range becomes sustained sensor coverage over the gap.