No one wins from trade protectionism and the return of Tariff Man, and retaliatory measures from Beijing will only exacerbate what was already shaping up as a testing period for financial markets and investment portfolios.

Equity markets began May showing signs of fatigue after a powerful rebound in recent months. That’s hardly surprising given that asset prices need to see stronger evidence of a resilient global economy, thereby signalling the current cycle has room to run longer.

That now looks a far tougher challenge after the US jacked up tariffs on $200bn of Chinese imports on Friday, a move foreshadowed by President Donald Trump last Sunday who duly rattled financial markets this week. An escalating trade war after a hiatus of several months takes us back to the final quarter of 2018, when markets approached the brink, only for central banks to come riding to the rescue.