Thomas Malthus was the person that affected and influenced Sir Charles Trevelyan's ideas about government intervention.
This is because, Sir Charles was a British official who was faced with the problem of scarcity of potato and Great famine in 1840 and his decision not to help the Irish was probably because of what was taught to him by his professor Thomas Malthus.
Thomas Malthus taught in his theory of population that population would increase while available food would not increase in the same manner and would cause large scale shortage.
The government was able to request money from the people for things the government needed but they could not enforce these requests so the government overall had little money and no effective way to get it