Background Indwelling urinary catheters are drainage devices inserted into the bladder and are held in place by an inflatable balloon. The use of urinary catheters, while essential to bladder management, places the user at risk of catheter-associated urinary tract infections. Prevention of such infections in long-term catheter users could improve quality of life, and antimicrobial catheters may be more cost-effective compared with current plain catheters. We have developed and extensively characterised an indwelling antimicrobial urinary catheter impregnated with rifampicin, sparfloxacin and triclosan. We aimed to assess the effect of the antimicrobial urinary catheter on the number of catheter-associated urinary tract infections, blockages, unscheduled catheter changes, quality of life and resource use compared to usual care, over a 1-year period. We also aimed to assess the relative long-term safety, acceptability and cost-effectiveness of the novel catheter compared to current practice. Methods Before the clinical trial could be undertaken, the antimicrobial catheters had to be manufactured and validated by an industry partner in a multistage process. Validation included impregnation, accelerated ageing and biocompatibility testing. Progress and challenges Extensive device testing methods were developed and validated, including methods for determining the antimicrobial content of the catheters, detection of residual solvents and for an accelerated ageing process. A randomised clinical trial protocol was developed in parallel, in conjunction with patient advocates. A Trial Steering Committee was convened and a network of urology clinics created. The most significant challenge was that the industry partner was unable to consistently manufacture antimicrobial urinary catheters to the product specification. Much closer oversight of manufacturers processing the catheters is necessary to ensure compliance with protocols. The regulatory requirements for the novel catheters were also more extensive than anticipated and are subject to change. Delays accrued from these challenges, and there was uncertainty around the ability of the industry partner to produce a catheter. Ultimately, the project funder withdrew the funding before the clinical trial commenced. Conclusion Catheter-associated urinary tract infections remain a serious problem, especially to long-term urinary catheter users, and there is currently no effective prophylactic strategy. Protocols for validation of impregnation and sterilisation steps for biocompatibility testing and accelerated ageing studies have been established and can be applied to future manufacture of antimicrobial urinary catheters. A protocol for a randomised trial of such medical device has been developed and can be deployed once a antimicrobial urinary catheter has been correctly manufactured. Funding This synopsis presents independent research funded by the National Institute for Health and Care Research (NIHR) Efficacy and Mechanism Evaluation programme as award number NIHR127982.