To my knowledge, that would never be categorical. At best, they could sometimes
be homophonous, never in Estuary English or RP, but maybe in Geordie or the Norfolk dialect. I'm not sure about either of them. Try to borrow Accents of English 2: The British Isles
from your library.
- /t/ in /VtV/ contexts is usually not pre-glottalised [ʔt] (it's plain wrong in RP), but is often glottalised to [ʔ] in informal speech.
- /k/ in the /VktV/ context is usually released in a "masked" manner, i.e. more or less simultaneously with /t/: [k̚t], and may also be pre-glottalized [ʔk̚t]. According to John Wells, a "non-masked" release [kt] sounds Welsh or South African.
- I suppose /k/ in the /VktV/ context could
be pronounced [VʔtV] in informal speech, but I'm not sure.
So, let's list all of the relevant UK pronunciations. NRP means "non-RP", and WO means "Wales only".fatter
[ˈfatə], NRP [ˈfaʔtə], NRP [ˈfaʔə]factor
[ˈfak̚tə], [ˈfaʔk̚tə], NRP [ˈfaʔtə] (?), NRP-WO [ˈfaktə], NRP-WO [ˈfaʔktə]
I'm not sure about (Northern) Ireland and South West England.
Further reading: http://www.phon.ucl.ac.uk/home/wells/glottals2-colour.pdf