The eurozone crisis never went away; it was just overlooked in the Brexit upheaval. But you can rely on Italy to trigger thoughts of catastrophe and, sure enough, the arrival of this weekend’s referendum on constitutional reform has spooked markets.

The yield on 10-year Italian debt has doubled from 1% to 2% since August, outpacing the rise in yields on most other eurozone sovereign debt. The euro has even weakened against the supposedly down-and-out pound. A euro cost 90p a month ago but now fetches 84p.

In the grand scheme, these are not enormous moves. Back in 2011-12, when the Greek debt crisis was in full swing, Italian 10-year yields hit 7%; and the euro is still 10% stronger against sterling since the UK referendum. But Italian risks – for the short, medium and long-term – are real.

The immediate danger will arrive if PM Matteo Renzi loses the referendum and then honours his pledge to resign. His departure would make it harder to resolve a crisis in the Italian banking system that should have been addressed half a decade ago and is now intense. It even got a special mention in the Bank of England’s UK financial stability report this week. The detail is extraordinary: bad, or non-performing, loans in Italy exceed the total provision for losses and the banks’ core capital.

The only solid cure is a combination of fresh capital and the infliction of financial pain on some classes of bondholders. The latter is politically explosive – because so many bank bonds are held by pensioners – but demanded by new eurozone restrictions on state-sponsored bailouts. As for injections of capital, the private sector will not volunteer if the country is without a prime minister for the next two months.

The medium-term risk is that the vacuum is filled by the anti-euro Five Star Movement led by comedian Beppe Grillo, currently riding high in the polls in the run-up to a general election that must be held by February 2018. Note, too, that planned electoral changes in Italy will give the largest party extra parliamentary clout in future. The overhaul is intended to prevent so many wobbly coalitions. But if Five Star is the first beneficiary, the eurozone will have a proper political crisis on its hands.

The long-term risk remains the same: Italy is stuck in an economic rut. Growth has improved slightly with Renzi’s market-friendly reforms – 0.8% is predicted for this year – but the Italian economy is still basically sluggish. Meanwhile, public debt is 130% of GDP and unemployment stands at 11.6%, above the eurozone average of 9.8%. The employment rate is just 57.2%; the UK’s is 74.4%.

It is too simple to say defeat for Renzi in the referendum will unleash a fresh eurozone crisis because one should never underestimate the power of the European Central Bank to buy time by suppressing bond yields. But the ECB’s powers are not unlimited and the quantitative easing programme cannot continue indefinitely.

The Bank of England’s stability report summed up the overall picture: “Risks associated with the euro area remain elevated.” You bet. And the Italian risks look acute.

Glencore’s dance with debt has hurt its chief

Ivan Glasenberg has hauled Glencore out of its debt hole, a task that looked daunting 18 months ago. Borrowings have been reduced from $30bn to $17.5bn by selling $6bn of assets, cutting expenditure and raising $2.5bn of fresh capital at 125p a share. Glasenberg, the chief executive, dipped into his back pocket to contribute $211m to the fundraising and has made a handsome turn. The share price is now 283p. It has been an impressive act of escapology, with dividends set to resume next year.

But Glasenberg’s status as the all-seeing sage of the mining world is surely ruined. Glencore’s dance with debt was absurdly aggressive in an industry where the next big downturn is never far away. The company has recovered through its own efforts but also through good fortune, in the form of a rapid rebound in the prices of copper, coal and zinc. Those commodities will have to keep humming along if Glencore is ever to return to its 2011 flotation price of 530p, which is a truer benchmark for success. Only an 87% improvement in share price to go, then.

Asos’s spirit of openness has its limits

“We have nothing to hide and much to be proud of,” declared Nick Beighton, chief executive of online clothing retailer Asos, in October when working conditions in the firm’s warehouse in Barnsley came under the spotlight. The spirit of openness has its limits, however. Beighton initially welcomed our reporter to Asos’s annual shareholder meeting on Thursday but then changed his mind and turfed him out before proceedings started.

Note to Beighton: if you want promote the idea that your working conditions are splendid, don’t adopt a bunker mentality.