The Brexit's reactionary financial downturn is already correcting itself...

[gratuitous]

5. There will be convulsions, to be sure

It may take quite some time for England to recover. The rest of the EU perhaps not so long. After all, England alone among the EU members continued to use its own currency; everyone else uses euros, and still does. The wallop the pound took was to be expected, but the rest of the EU member nations aren't that tied to the pound, and certainly not as tied as they are to the euro.

Other countries contemplating their own departure would have to decide whether to divest from the euro and re-institute their own currency, or stay on the euro to smooth out the effect. Staying with the euro might cause any number of countries to wonder, "Why bother, if we're just going to have the same currency?"

As for credibility, it remains to be seen whether (for example) the broken promise that the "savings" from leaving the EU were going to be invested in the national health will damage the conservatives. One or two Brits have already expressed some dissatisfaction with that.