Britain wants to pick up the pace. EU negotiators in Brussels are taking their time. Blackmail and sabotage, cry Westminster's Brexiters. The explanation is more prosaic. The more urgent a deal begins to seem for Britain, the higher the incentives stack in favour of a stalling strategy from the EU27.
This, of course, is how the process was designed. Article 50 of the union's treaty was written to discourage nations from leaving. As soon as Theresa May set the article's two-year clock ticking in March, she conceded the advantage to those sitting on the other side of the table. The prime minister was warned of the danger by her advisers. But that was before she had lost an election and Britain had to confront the hard reality that it cannot have its cake and eat it.
The problem for Mrs May is that the structural asymmetry written into the treaty - the cost of a no-deal, cliff-edge exit is much higher for the departing nation than for the rest - is being reinforced by the particular circumstances of Brexit.
With the exception of Ireland, even those EU governments hopeful of strong post-Brexit ties see a useful purpose in spinning out the talks. After all, it may still be possible, they can speculate, that the dire prospect of crashing out of the bloc might yet persuade the British to think again.
More obviously, there is little to be gained by the EU side in striking an early deal with a government that is still negotiating with itself over what sort of Brexit it actually wants. The television cameras may be focused on the bargaining in Brussels, but most of the big arguments are still happening in London.
Mrs May has edged towards realism by accepting the need for a post-Brexit transition period which would not look much different from the status quo - except that Britain would be demoted from the role of rulemaker to that of rule-taker.
She is still some distance, however, from owning up to the eventual loss of access to Europe’s markets. Britain cannot simply swap membership of the single market and customs union for bilateral arrangements that provide business with the same advantages.
In the circumstances, it makes perfect sense for Michel Barnier, the EU's chief negotiator, and his team to allow the pressure of time to build up before agreeing to move on from discussions about past financial obligations and the rights of EU citizens to talking in detail about the shape of the future relationship.
Politics pulls in the same direction. Mrs May’s ill-fated election gambit robbed the prime minister of her personal authority and her government of its majority. There is no guarantee that she could actually deliver anything agreed in Brussels. The incentive is to let the clock do its work. How long now before an anxious business community takes irrevocable decisions to shift some shipping operations from Britain to the continent?
Mrs May thinks she has an answer. The logjam can be broken by direct talks with other governments. More specifically, once the German elections are over on September 24 a re-elected Angela Merkel can be prevailed upon to give a helpful nudge to Mr Barnier to pick up speed.
We have been here before. Misreading Bonn and later Berlin has been one of the more reliable threads of 44 years of British EU membership. Germany, the thinking in London goes, is an outward-looking, Atlanticist nation with, by continental standards, a liberal economic bent not far removed from that of Britain. The UK is one of German industry's richest markets. These are two nations on the same side.
Mrs May's predecessor and author of the present debacle David Cameron made precisely this calculation when he sought before the Brexit referendum to win over Ms Merkel to British demands for EU reform. The chancellor held firm in defence of the integrity of the existing framework of rules. Now Mrs May seems intent on repeating the mistake by expecting Ms Merkel to bend the EU's rules to accommodate Britain's departure.
But Germany has its own politics and interests. The opinion polls may be unanimous in predicting a fourth term for the chancellor, but they are far less clear about how she will assemble a governing coalition. For the next couple of months securing her own position will come far ahead of bailing on the British.
As for European policy, the first priority for Berlin is to assure the stability of the 27. The terms of another bailout for Greece, deepening integration in the eurozone and measures to strengthen the borders of Schengen all rank above Brexit on Germany's European agenda.
To borrow an unfortunate phrase, Ms Merkel’s message to Mrs May is that Brexit means Brexit: Britain cannot leave the EU and expect to escape the consequences.
For Germany, the integrity of the union depends on preserving the rules. Those who step outside cannot keep the benefits. Ms Merkel does want a good relationship with the UK. But Germany has the Europe it wants. It is not about to give it up for Mrs May.
The writer at present is a Richard von Weizsäcker Fellow of the Robert Bosch Academy in Berlin
FT Service