Background A study within a trial (SWAT) can be used to compare the effectiveness of various recruitment aids. In this SWAT, we assessed the impact of incorporating a pictorial aid into an enhanced Patient Information Leaflet (PIL) versus utilising a standard PIL, nested within a trial comparing adjuvant therapy alone with adjuvant therapy plus axillary treatment for women with early-stage breast cancer with metastases in one or two sentinel nodes (the POSNOC trial). Methods The pictorial aid was designed to illustrate the treatment procedures in both arms of the POSNOC trial for potential participants. POSNOC recruiting sites were cluster randomised to provide potentially eligible women who were approached about taking part in the study with either the enhanced PIL or the standard PIL. Allocation was stratified by recruitment activity in the 12 months preceding the SWAT. Results Eighty sites participated in the SWAT, with 40 randomised to each arm. Between December 2019 and July 2021, 258 participants were recruited. The enhanced PIL group recruited 117 participants (mean = 2.9 per site) while the standard PIL sites recruited 141 participants (mean = 3.5 per site). There was no evidence of a between-group difference in recruitment (adjusted difference in mean in enhanced vs standard PIL = -0.68, 95% CI -1.99 to 0.63, p=0.31). Conclusion The study found no evidence that an enhanced PIL increased recruitment compared with the standard PIL. These data may contribute to future systematic reviews of randomised studies of recruitment interventions.