When David Cameron addressed Australia’s Parliament last November, the British prime minister referred briefly to the Square Kilometre Array (SKA), “the world’s largest radio telescope”. The project’s headquarters, he noted, were in Manchester, UK. Not so. The location of the SKA headquarters — a political and scientific prize — was due to be decided last week. It was a two-horse race: the United Kingdom or Italy. But the date came and went with no news. Astronomers have been left scratching their heads.

Nature has seen internal documents that explain both the delay and Cameron’s expectancy. Italy won, and the United Kingdom kicked up a fuss. It threatened to pull out. It implied that Italy could not be relied on. It demanded (and will get) a recount. It acted, in other words, as a playground bully. Science has never been immune to the ugly reality of politics, but last week’s unseemly gamesmanship is a particularly sorry example, and one that should not be allowed to stand unchallenged.

It is true that the Jodrell Bank Observatory near Manchester has acted as a temporary base for the SKA since 2012, and that the British would like that to continue. But the merits of two possible sites for a permanent home — the other is a historic observatory in Padua — have been the subject of an admirably transparent selection procedure, which the United Kingdom is now trying to undermine.

The two bids were assessed on a precise set of criteria, including political commitment to provide the extra financial support expected of a host and the quality of the research environment. The SKA board agreed on a timetable and chose a selection panel to assess the bids and recommend the winner. The panel comprised SKA board directors from three of the organization’s 11 member countries — Australia, South Africa and the Netherlands — and a representative from the European Southern Observatory (ESO), an international astronomy organization headquartered in Garching, Germany. The panel’s recommendation to the SKA board last week was crystal clear: both locations satisfied the criteria, but Padua was the better option.

When the United Kingdom saw that it had not won, it tried to change the rules, ramping up the pressure by circulating government-level letters to SKA board members. One from the head of the UK Science and Technology Facilities Council says “the [panel’s] report does not appear to properly account for the scale and approval status of our financial commitment”, and that “any decision on the headquarters must consider the broader ways this will affect the project and in particular the way in which it could affect the level of political commitment to the project”. Another (unsigned) letter from the UK Department for Business Innovation and Skills says: “All things being equal — which they are in terms of meeting the HQ criteria — it makes no sense to dramatically increase the risk of the project by changing leadership from the UK to Italy … Transferring leadership would require the UK to radically re-assess participation in the project.”

Science has never been immune to the ugly reality of politics.

The SKA aims to use the globe as a giant radio telescope to image the early Universe, when the first stars and galaxies were forming. With a project this ambitious, it is perhaps not surprising that fights for control get dirty. In March 2012, South Africa was judged slightly better as a site to host the SKA telescope than Australia, but a political storm led to the decision to share the instruments. South Africa is building 3,000 dishes, and an even larger number of antennas are being installed in Australia.

Any competition for hosting the headquarters would have been undertaken in the knowledge that a non-UK winner would require a physical move. Italy may have a reputation among tabloid newspaper readers as Europe’s clown — thanks in part to years under former prime minister Silvio Berlusconi— but hard-nosed scientists looking at its reliability in international scientific projects do not need to stoop to stereotypes. Italy is a reliable partner in both CERN, Europe’s particle-physics lab near Geneva, Switzerland, and the ESO, for example. The country has competently headed organizations including the International Centre for Theoretical Physics and the International Centre for Genetic Engineering and Biotechnology for decades without problems.

Under pressure from the United Kingdom, the SKA board deferred a vote on the headquarters site to its next meeting at the end of April. It gave both countries until 20 March to submit extra material to the selection panel to confirm financial support, including their commitments if they are unsuccessful, and to address vague “operational and schedule matters; and organisational and reputational matters”. The board also asked the panel to provide it with a comparative analysis “without an overall recommendation” by 10 April. These new criteria represent a move away from a transparent selection process to one that is based on murkier ground.