Background <p>Picture-naming tasks are widely used for identifying speech-eloquent regions during awake craniotomy. However, language-specific and culturally relevant task stimuli remain scarce. Current practices mostly rely on translated stimuli that do not reflect the everyday language use of the target speakers and might be susceptible to misinterpretations due to linguistic and cultural differences. Additionally, non-standardised homemade tasks are used. Here, we, for the first time, present the development, standardisation, and clinical application of two tests designed specifically for functional mapping in British English.</p> Methods <p>115 object and 86 action stimuli were developed using the British National Corpus (BNC) and controlled for confounding psycholinguistic variables using normative data from native speakers. Optimization of the items for intraoperative use was done by first standardising the tests in healthy volunteers followed by their application during the electrical stimulation of language-eloquent regions in brain tumour patients. In the standardised data, the influence of word- and subject-related factors on performance, and the test-retest reliability was explored.</p> Results <p>The final items achieved above 80% naming agreement. Object naming proved easier compared to action naming, with accuracy positively influenced by word frequency and negatively affected by the age-of-acquisition variable in both tasks. No subject-related effects were found. Excellent test-retest reliability confirmed the consistency of the tests in measuring language abilities. Positive maps obtained during intraoperative functional mapping demonstrated the sensitivity of the tests in detecting speech-eloquent regions.</p> Conclusion <p>The tests provide a reliable and robust tool containing stimuli that are linguistically and culturally appropriate to British-English speakers.</p>