The UK response to the Salisbury poisoning attacks of 2018 was a triumph and provides valuable lessons in information advantage and grey-zone competition for the national security establishment. From the poisoning of the Skripals in March to the unravelling of the GRU’s operations in October, the UK conducted a phased, managed confrontation, reaching a defined end state. Characterised by the need to establish clarity, authority and authenticity, the UK used an ‘elastic communications strategy’, which blunted Kremlin disinformation and leveraged the full spectrum of government powers into a potent ‘second strike’ communications response. The case demonstrates that successful and innovative grey-zone competition can be achieved without sacrificing moral authority.◼