Working women are being encouraged to bill the Prime Minister directly for the money they're not getting due to the gender pay gap. The campaign launched today by the group STILL Minding the Gap is calling on the government to introduce mandatory gender and ethnic pay gap reporting for businesses. At the moment it's voluntary. The group said making it mandatory would shrink the gap between 20 and 40 percent. STILL Minding the Gap campaign manager Jo Cribb spoke to Lisa Owen.