Reasons for british economic slump after wwi?

Because they had just poured all of their resources into fighting a war with France, Russia, and later the US against Germany and Serbia (I think). I mean they have to buy weapons, transportation, not to mention that they had to train their men. That costs lots of money. The US loaned the Allies about 16 billion dollars. Plus many of the men had died in the War so the work force was not back up to its pre-WWI levels. Not to mention that America was an idiot and raised tariffs to nearly 50 % thus making it near impossible to trade with the US, who was pretty much the only country not in debt. And with no trade, the British had no way to return to its pre-WWI economy. Plus the US also demanded that the British and French repay all of the money that the US had loaned thm during the War even though they were alliances.