As for rewriting nuclear rules, some governments will resist using the NPT conference to strengthen the badly weakened treaty on the ground that the nuclear powers have still not done enough.

Tory backbenchers have urged David Cameron to take the opportunity of any treaty changes arising from the crisis to repatriate powers from Brussels to Westminster.

Beyond the euro crisis, the Lisbon treaty has given new powers to the European Parliament, a maddening assembly addicted to regulation and public spending.