Personnellement, j’ai toujours dit et entendu dans mon entourage (je suis Parisien) :

V, I, deux L, E

As a French person, it is "deux". I never heard "double" and would find it a bit odd.

Although you can still spell the letter twice. (But be aware of the possible confusion. Some people might not be sure if you just repeated the letter for clarity.)

As the other answers mention, this is "deux" and not "double".

A few words about the usage: for someone who started school in the late 70’s, we have been taught to spell V I deux L E (western suburbs of Paris).

Nowadays, I hear more and more the spelling V I L L E. My wild guess is that this is because we are more often spelling in foreign languages (or native words to foreign languages), where everyone will spell letter by letter (it would not make sense to spell VILLE in English using the word "deux")