How does The Gambia’s place in the world economy differ from, say, the place of Britain? How does that place affect The Gambia? What do you think would be necessary for The Gambia to move from “Third World” to “First World”?

First, The Gambia is a very small country, with a tiny economy compared to that of Great Britain or any other European nation of similar size. The country's GDP is very small and has, for several years, been in a state of recession. Its economy is centered around agriculture, which means that it is very susceptible to severe economic downturns in the event of drought or other things that limit agricultural output. There is a relative lack of capital for domestic investment, so the country experiences very high debt relative to its GDP. Like many countries with widespread poverty and with little money to invest in education and infrastructure, The Gambia struggles to maintain even modest economic growth. The economy of Great Britain, on the other hand, is huge. Britain remains a very important player in the world's economy. Its GDP in 2016 was over 2.6 trillion dollars. While British manufacturing is in decline, its economy is highly diversified. The technology and infrastructure that exist in the United Kingdom give it an immeasurable advantage over small, impoverished nations like The Gambia. In order to close this gap, The Gambia would need substantial investment in infrastructure, including roads, communication, and so on. It would also need large amounts of foreign investment. Above all, the economy of The Gambia would have to diversify. This is, of course, very difficult for a small nation like The Gambia.
https://www.worldbank.org/en/country/gambia/overview

https://www.worldbank.org/en/country/unitedkingdom