Note no lessons learned from the Irish Potato Famine. Still don't know if the British have learned that lesson yet.
Plenty of lessons were learned from the Indian famines of the 19th C, which led to them largely disappearing in the 20th C until the Bengal famine which happened in the middle of WW2.
They had, at times, been guilty of not applying what they had learned though.
But his government was a EMPIRE, and should of acted like one in this time by getting food from elsewhere within it's own supply lines, as well as moving people out.
They did get food from elsewhere, just not enough. With the benefit of hindsight and knowing the final outcome of WW2 and not actually having to find any of this food, it's easy to say they should have got as much as necessary and found means to get it to where it was needed, whatever it took.
Harder to do when it requires taking food away from another area with shortages, taking ships away from other areas of operation with shortages, safely getting those ships thousands of miles through mined seas patrolled by hostile navies and air forces, etc. while operating under great uncertainty in a war that could still be lost and where logistics were incredibly complex.
Saying that they should have done this assumes there was an evidently superior solution to this problem that folk chose not to follow.
A lot of people made bad decisions and judgements, particularly at the start of the famine, but there was no easy solution to simply create food and logistics at will, especially by the time it became a cabinet level issue.