On 20 June 2012, an ATR72 level at FL140 and a climbing opposite direction Jetstream 32 received and correctly responded to co-ordinated TCAS RAs after ATC error. The controller had not noticed visual MTCD and STCA alerts and had attempted to continue active controlling after a TCAS RA declaration. The Investigation observed that the ineffectiveness of visual conflict alerts had previously featured in a similar event at the same ACC and that the ANSP had advised then that its addition was planned. TCAS RA response controller training was considered to be in need of improvement to make it more effective.