It seems strange to me that both Portugal, with its strong ties to England, and Spain, with its historical hatred of England and the promise of new Portuguese holdings, both remained neutral throughout the entirety of the war. Why was England so intent on Portuguese neutrality despite their control over several key tactical islands like the Azores and the possibility of a direct land route into France? Wouldn't a complete blockade of the west Atlantic be very advantageous for Nazi Germany? If they held Gibraltar, couldn't they cut the allies off from the Mediterranean and prevented the invasion of Sicily?
This is a common question so here are some previous answers i could find:
On the topic of Spain there are many, this one by u/tobbinator is good to start with but there are many more.
I found less on Portugal but this one by u/vonadler
Here's a bonus one about a treaty between Britain and Portugal which also disgusss this topic.