As the US retreats, Europe must look out for itself – so is Macron’s nuclear offer the answer? | Simon Tisdall

Development of a joint defence shield would be politically explosive for Keir Starmer. But it's an idea whose time has come

The startling contempt for Europe's intensifying security concerns displayed by Donald Trump and his henchmen has brought an old, controversial question back to the fore: should Britain and France pool their nuclear weapons capabilities and create a Europe-wide defensive nuclear shield to deter Vladimir Putin's Russia, if the US reduces or withdraws its support?

Trump has not so far explicitly threatened to cut US nuclear forces based in Europe. But speaking last week, the president said he wanted to halve the US's defence spending, especially on nuclear weapons. Trump often denigrates Nato, keystone of European security. Last year, he encouraged Russia to do whatever the hell they want" to member states that, in his view, spend too little on defence.