I did some searchings and I found the following

1)During the famine(45/48)1.257 million ton of wheat was leaving Ireland,but 1.603 million ton was imported

2)Before the famine, yearly 3 million people survived on potatoes only(the others were eating potatoes and other things),which meant yearly 3.65 million ton,for the famine = 14.6 million .

3)This means that the wheat that was leaving Ireland was not even 10 % of the potatoes which were needed for the survival of 3 million people .

4)Besides, what would the poor in Ireland do with wheat ? You can't eat wheat .


Conclusion : to prevent the disaster of 1845/1848, not wheat was needed, not meat, but potatoes,and these were not available,as the same disaster (on a lesser scale) happened on the continent .

There was nothing to do,unless to try to alleviate the situation,which Britain did, to late and to little ,but nothing could prevent the disaster in Ireland .



Wheat exports and imports from and to Ireland (in 1000 of tons)


Exports

1844:424

1845:513

1846: 284

1847 : 146

1848: 314


Imports

1844 : 30

1845 : 28

1846 : 197

1847: 889

1848: 489

From "Black 1847 and beyond:the great Irish famine in history(Cormac O'Grada) P124:


Though official neglect and endemic injustice played their part in 1846/1847,there is no denying that the Irish famine,was at least in 46/47,also a classic case of food shortage .


From the same work : Table 4.1:

Grain exports (in thousand of quarters) between 45/48:8.047

Grain imports :7.839

Imports of Maize :5.481


Before the famine, the yearly potato harvest was 20 million ton (of which 10 million was reserved for the animals).

How could one replace these 20 million ton? By stopping the export of pigs ??