What the hell is the European commission playing at? Don’t they know they risk seeing financial markets fall off the edge of a cliff?

The sober suits on the Bank of England’s financial policy committee did not put it like that, but one could catch their drift. When the Bank describes a “pressing” need for EU authorities to take “mitigating actions”, it means the position is serious. So it is: Threadneedle Street is talking about financial derivatives contracts worth £69tn, of which £41tn could conceivably have to be moved before next March, a task that would be either hideously expensive or impossible to achieve.

The numbers almost sound too big to be meaningful but the derivatives market really is enormous. In fact, the £69tn and £41tn figures relate only to the notional size of the contracts held by EU-based firms at UK-based clearers, outfits that stand in the middle of the market to clean up any mess. Those contracts – interest rate and currency swaps and so on – are the everyday business of financial markets and ultimately serve to keep money flowing and reduce borrowing costs. To avoid mayhem next March, this stuff has to continue to work.

On the UK side, the Bank says we have almost done our bit. The government is legislating to ensure UK businesses can use EU clearers after Brexit. But EU authorities have not indicated they will do the same in reverse, which is astonishing in many ways. First, EU-based firms clear 90% of their derivatives in London. Second, EU clearers do not have the capacity to absorb £41tn of contracts in a hurry. Third, the biggest losers without an agreement would be EU businesses.

If left alone, the technocrats could probably solve the problem before lunch. The Bank and the European Central Bank in Frankfurt have a joint working party that is said to be working happily. The finger of suspicion, therefore, points at Brussels. Is the commission playing games of brinkmanship to try to drive financial business out of London? Or does it seriously believe – as nobody else does – that firms can rejig the contracts in the remaining time?

Whatever the explanation, the Bank is probably sick of issuing dire warnings. It has been shouting about the risks to financial stability since last December. Financial markets have been sanguine, probably believing common sense will prevail, which is still the most likely outcome regardless of what happens with the wider trade talks. But one almost wishes markets would throw a tantrum. A no-deal Brexit, if it were to mean no deal whatsoever on derivative contracts, would be an absurd calamity.

Aviva caught between BlackRock and a hard place

For a certain breed of chief executive, a seat on the board of BlackRock, the world’s largest asset manager, is a serious prize. It is a sign you are a player on the global stage, fit to share visionary thoughts with similarly high-minded corporate titans.

Mark Wilson at Aviva always gave the impression he viewed the BlackRock gig as too juicy to resist. He took the part-time post in March in defiance of complaints from some Aviva shareholders and the private muttering of colleagues. Doubters reckoned the chief executive of a large FTSE 100 insurer, especially one with a competing fund management business, should stick to the day job.

The critics have won that little quarrel. Wilson was pushed out of Aviva on Tuesday, accompanied by praise for past achievements but also the stinging comment from its chairman, Sir Adrian Montague, that “this is the right time for a new leader to ensure Aviva delivers to its full potential”.

Mark Wilson always gave the impression he viewed the BlackRock gig as too juicy to resist. Photograph: Peter Nicholls/Reuters

Changing the boss looks fair. The BlackRock posting was no deal breaker but it reinforced the impression that Wilson, after six years in post, was more interested in his next career move than in finding ways for Aviva to grow. Wilson’s cleanup of the chaos he inherited at the insurer in 2013 was impressive and the dividend recovery was strong, but you can’t live off turnaround glories for ever. The share price has gone nowhere since the takeover of Friends Life in 2015.

The fiasco of Aviva’s attempt to redeem “irredeemable” preference shares cannot be laid solely at Wilson’s door since the move was approved by the whole board. But the grumble in the wings that the boss had lost the support of his fellow executives rings true. In the circumstances, Montague & co had little choice but to act. When the chief executive is on a pay package worth more than £6m a year, it is reasonable to expect his full attention.