/r/badeconomics has a thread right now contending that this is basically a myth. Some of the claims made there make sense, but others aren't as convincing. And users seem to be generally relying on wikipedia & The Economist, which are fine but not the greatest sources. Now I know Simon Schama has written in defense of the notion & one of the original popular histories of the Great Famine (The Great Hunger) did as well. Charles Kindleberger, afaik one of the best-known economic historians of the 20th-century, was supporting this idea as late as the 1980s. So, what's the historical consensus on this? Is there something more definitive today that I could read on this maybe from an actual economic historian or cliometrician?
I took a look at the link you posted and it's not a very well informed discussion. At least someone cited Cormac Ó Gráda who is one of the best historians of the Famine. Another, Jim Donnelly wrote a good summary for the BBC here http://www.bbc.co.uk/history/british/victorians/famine_01.shtml
There is was a big shift in policy by the British government in 1846 which ended the public works and food supplies that had been provided up to then. This was largely an ideological decision though public support for Famine relief was waning and it was proving very expensive. Laissez-faire was also behind the decision not to close the ports which would have reduced food prices. There is really no debate about this. There is a debate about to what extent British policy was negligent and how much it was malicious. Traditional nationalists have taught that the British State deliberately exacerbated the Famine to kill off the Irish whereas modern historians believe it was a more complex process. [typo edited]