‘Get Brexit done, then Arpa’ read Dominic Cummings’s WhatsApp profile. Arpa was what’s now the American Defense Advanced Research Projects Agency. Mr Cummings has departed, but our very own British Arpa has arrived. Downing Street has tweaked the Yankee acronym to ‘Aria’ — the Advanced Research and Invention Agency. Its aim? ‘High-risk, high-reward’ scientific research.