O F ALL THE possible obstacles to Britain’s smooth exit from the European Union, few can have seemed less likely than Moldova. But on October 17th the little republic roared. In June Britain filed to rejoin the Government Procurement Agreement (GPA), part of the framework of the World Trade Organisation (WTO). It now finds its bid unexpectedly blocked. A country of 3m people, whose largest exports are insulated wire and sunflower seeds, stands between Britain and a global public-projects market worth $1.7trn a year.

The GPA lays out open, fair and transparent conditions for businesses competing in government-procurement markets. The agreement has 19 parties, of which some are multi-member organisations like the EU. Britain takes part only by virtue of its EU membership. For British companies to retain their equal footing in bids abroad after Brexit, Britain must be readmitted. If not, companies like Serco Group, the global government-services provider whose American subsidiary won a $1.3bn commission to administer aspects of Obamacare in 2013, could lose lucrative gigs. Moreover, lapses in the agreement could disrupt the complex supply chains of firms in industries such as pharmaceuticals.

The wrath of Moldova seems to have been sparked by a personal affront. Last year Corina Cojocaru, Moldova’s economic counsellor to the WTO and wife of Moldova’s foreign minister, suffered the indignity of her and her colleagues’ British visas being withheld for several months after they planned to make an official visit to the country. In blocking Britain’s bid to rejoin the GPA, Moldova cited worries that its companies might face the same hold-ups as its envoys. It called for simplified visa procedures for its citizens and firms.

Moldova is not the first country to query Britain’s application. America and New Zealand have also held it up, while several others have expressed concerns. But those countries’ complaints are administrative, regarding missing information about post-Brexit trade relationships. Moldova is the only country with a substantial complaint.

It is likely to be cleared up in time. Once the administrative gripes of other countries are sorted out, Moldova is unlikely to stand alone against Britain. But Britain is again reminded of its weak negotiating position. Though it vaunts its own procurement market, worth some £68bn ($88bn) a year, it is bidding for access to a global one 20 times that size. Other countries may use the situation to extract concessions, such as preferential terms in post-Brexit trade negotiations. Moldova’s stand shows that demands can come from unexpected places and for obscure reasons. Mihai Popsoi, a Moldovan opposition politician, suggests that his country’s government is seeking token concessions to improve its poor popularity at home.

Moreover, the idea that Britain can at least revert to WTO rules has long been taken for granted. As leaving the EU without a deal becomes a growing possibility, bolstering WTO agreements becomes more urgent. With the WTO knee-deep in problems of its own, from trade wars to blocked judicial appointments, its director-general, Roberto Azevedo, has signalled that a “bumpy road” lies ahead for Britain.