We partnered with the Ministry of Defence (MOD) to find ways to reduce their gender pay gap. We designed an intervention to diversify the range of people employees organically share new vacancies with by explicitly encouraging staff to share vacancies with underrepresented groups: targeted referrals. We also encouraged managers to participate with a friendly competition between departments. Like many organisations, MOD does not have a formal incentivised referrals scheme, so findings from this trial could apply to a wide range of male-dominated companies.