People with secondary progressive multiple sclerosis (SPMS) often have problems with walking and balance, which lead them to fall. Undertaking exercise and learning about falls prevention could help reduce injury risk and improve mobility. We developed a mobility, balance and falls programme called Balance Right in MS (BRiMS). Before testing its effectiveness in a large-scale trial, we needed to conduct a small-scale version of the trial. We asked people with SPMS who had balance and mobility problems to be assigned by chance to undertake the BRiMS programme plus their usual care, or to continue with usual care only. Questionnaires were used to ask people about their mobility, falls and quality of life, and we measured their balance and activity levels. We interviewed participants about BRiMS and being in the trial, and collected information about costs. Fifty-six people entered the trial from three areas of the south-west and from Ayrshire. At completion of the study we were able to review 44 people. The key measures were completed by 98% of those we assessed, but only around half (62%) of the diaries detailing falls were returned. As this was a feasibility trial, the numbers were too small for us to look at differences between the groups. Participants liked the BRiMS programme; some did a lot of exercise and learning activities, but most did not manage the amount we asked them to do. People reported feeling a little overwhelmed by the educational content of BRiMS, and that this should be reduced in future. They told us that they felt that their balance had improved and that they fell less frequently after the BRiMS programme. Our assessment of the trial methods we used showed that it would be possible to conduct a full-scale trial using this design, but that we need to adapt the BRiMS programme further to make it more user-friendly.