Prefixes inter and intra

To me, the way many British people say the word "internet" sounds somewhat like my pronunciation of the word "intranet". To me they are

internet /"In@`nEt/
intranet /"IntS@nEt/

The same goes for words like international and intranational. Any thoughts?

Well, I don't think so. At least not in my accent, mate.

internet: /"Int@net/

intranet: /"Intr@net/

In British English, /t/ is clearly uttered. I like that feature.

eito(jpn), you mean Received Pronunciation, not English English as a whole (and no, not British English, as British English refers to the literary language, not the spoken language, as there is no single spoken "British English"). You must remember that glottal-stopping of /t/ is present in Cockney, Estuary English, and many Estuary-influenced varieties of English Engilsh, which is not exactly what one'd exactly call "clearly uttered".

Oh! I didn't expect what I meant was Received Pronunciation. And I completely had forgotten about that glottal stop of /t/, as in "written". I stand corrected. Thank you, Travis.

I was just clarifying that what you were speaking of is just specific to RP, rather than being a common feature in all of English English. On that note, I'm not sure if (at least conservative) RP actually glottal-stops the /t/ in "written", even though, say, Estuary surely does.

<<On that note, I'm not sure if (at least conservative) RP actually glottal-stops the /t/ in "written", even though, say, Estuary surely does.>>

I think it would usually be glottal-stopped in RP. Most EngEng sources that I've seen (like my Webster's New World Spanish-English Dictionary, which shows pretty conservative RP pronunciations) transcribe "written" as [rItn], with a syllabic n rather than a schwa + n sequence.

By the way, I pronounce the two words in question as:

internet [Int@`nEt]
intranet [Intr\@nEt]

(Reduction of /nt/ to [n] tends to be more limited in my dialect than in most other varieties of NAE - I generally pronounce the prefix "inter" with [nt] rather than a simple [n].)

I myself pronounce them as

"internet" : /"Int@`%nEt/ -> ["I~.4~@`.%nE?]
"intranet" : /"Intr@%nEt/ -> ["I~n.tSr\@~.%nE?]

As can be seen above, I do not reduce intervocalic /nt/ before an unstressed vowel to [n] but rather to [4~], and furthermore, I maintain the length of the preceding vowel as short, whereas if /n/ rather than /nt/ were present and the preceding vowel were stressed, then it would be long.

I usually say "innernet" (only occasionally "internet") and I can't say I've ever said "intranet" at all.

For me, even though many people informally transcribe the pronunciation of NAE "internet" as "innernet", writing it like that does not actually accurately represent how it would be pronounced in my dialect, as that would have the wrong vowel length and would not use a nasal flap:

*"innernet" : /"In@`%nEt/ -> ["I~:.n@`~.%nE?]

Of course, vowel length probably is more important in my dialect than most NAE dialects (and I do not mean RP-type vowel length, but rather allophonic vowel length), and also I actually have nasal flaps which are not simply in (semi-)free variation with alveolar nasal stops, unlike many NAE dialects for which such is not present or is not as consequential.