According to Hughes et al., the pronunciation of poor with the vowel /ɔː/ instead of traditional /ʊə/ has become increasingly common, leading to homophony with words like pour and pore (2012: 50). Hughes et al. do not offer any insight into the geographical distribution of speakers with this pronunciation, which suggests that it is quite widespread throughout the UK.
Homophony between pour and poor is clearly predominant throughout England, with the only exception being the North East, where only 34% pronounce the words the same (compare this with the 85% figure for the UK as a whole). The difference is even starker in Scotland and Northern Ireland, where the words are prounced the same for only 27% and 18% of speakers, respectively. There are less obvious pockets of speakers in Cumbria and just north of Sheffield who also pronounce these words differently.