In any divorce, lawyers are the only surefire winners, and as Britain muddles through one of the biggest, messiest and most complicated breakups in economic history, the country’s top law firms are booming.

Brexit, as Britain’s separation from the European Union is known, is just one of many reasons that the highest-grossing firms are enjoying their best results in a decade. Virtually every practice area is thriving.

Regulatory lawyers, those steeped in the staggering legal minutia produced by Brexit, have lately gone from drudges to rainmakers. These attorneys strategize with clients for life after Europe’s single market, consultations that often end in bewilderment and rage.

“There’s been some swearing, some clients whose faces have drained of color, when they realize the sort of impact this all will have,” said Andrew Hood, a regulatory and trade partner at Fieldfisher, a London-based firm with more than 1,000 lawyers. “And in the last six weeks, the number of clients who have woken up worried about what a no-deal Brexit looks like has doubled or tripled.”