Aims In 2015, colistin‐resistant Escherichia coli and Salmonella with the mcr‐1 gene were isolated from a pig farm in Great Britain. Pigs were subsequently monitored over a ~20‐month period for the occurrence of mcr‐1‐mediated colistin resistance and the risk of mcr‐1 E. coli entering the food chain was assessed. Methods and Results Pig faeces and slurry were cultured for colistin‐resistant E. coli and Salmonella, tested for the mcr‐1 gene by PCR and selected isolates were further analysed. Seventy‐eight per cent of faecal samples (n = 275) from pigs yielded mcr‐1 E. coli after selective culture, but in positive samples only 0·2–1·3% of the total E. coli carried mcr‐1. Twenty months after the initial sampling, faecal samples (n = 59) were negative for E. coli carrying mcr‐1. Conclusions The risk to public health from porcine E. coli carrying mcr‐1 was assessed as very low. Twenty months after cessation of colistin use, E. coli carrying mcr‐1 was not detected in pig faeces on a farm where it was previously present. Significance and Impact of the Study The results suggest that cessation of colistin use may help over time to reduce or possibly eliminate mcr‐1 E. coli on pig farms where it occurs.