"To attribute it to a deliberate policy of genocide on the part of the British government"

Maybe not genocide, but certainly little desire to aid the situation. Anyone who defends the British government during this period is ignoring the British governments own writings on the subject. This was not a 6 month famine. It lasted years. little was done, unlike in the rest of Europe. And yes, the majority of the population loss was due to emmigration - thank goodness. imagine how many more would have died if emmigration wasn't possible (See the famine that killed millions in 20th Century China, for an example).