This study is a formant-based investigation of the vowels of male speakers in 13 accents of the British Isles. It provides F1/F2 graphs (obtained with a semi-automatic method) which could be used as starting points for more thorough analyses. The article focuses on both phonetic realization and systemic phenomena, and it also provides detailed information on automatic formant measurements. The aim is to obtain an up-to-date picture of within- and between-accent vowel variation in the British Isles. F1/F2 graphs plot z-scored Bark-transformed formant frequencies, and values in Hertz are also provided. Along with the findings, a number of methodological issues are addressed.