A hidden infrastructure of pushbacks? The Poros centre, at one level, illustrates how the function of such border facilities can change over time, as the local border regime adapts and responds to migratory movements. Fylakio has become the main reception and detention centre in Evros, and between 2015 and 2017, the Aegean islands became the main point of entry into Greece and the European Union. Yet, our findings raised a lot of significant questions regarding the new function of Poros, given the increase in migratory movements in the area since 2018. While we obtained official confirmation that the Poros centre is now used for temporary detention and not screening, it remains the case that there are no official documents – including any administrative acts on diavgeia.gov.gr – that confirm its use as a temporary closed detention centre. Equally, we did not manage to obtain any information about how the facility is funded from the Hellenic Police. Our respondent did not know, and another departments we called did not want to share any information about the centre. It also became evident in the course of our research that most of our contacts in Greece – NGOS and journalists – had never heard of the facility or had no recent information about it. We found no evidence to suggest that Greek and European human rights bodies or NGOs which monitor detention facilities have visited the Poros centre after 2015. A mission of the Council of Europe (2019), for example, visited several detention facilities in Evros in April 2018 but the Poros centre was not listed among them. Similarly, the Fundamental Rights Officer of Frontex, in a partly joined mission with the Fundamental Rights Agency, visited detention facilities in South Evros in 2019, the operational area where the Poros centre is located. However, the centre is not mentioned in the report on that visit (Frontex, 2019). The dearth of information and absence of monitoring of the facility means that it is unclear whether the facility provides adequate conditions for detention. While our Hellenic police informant stated that detention there lasts for one or two days, there is no outside gate at the Poros centre, just a rather flimsy looking wire fence. Does this mean that detainees are kept inside the main building or containers the whole time they are detained there? We also do not know if detainees have access to phones, legal assistance or healthcare, which the articles in the local press suggest that is absent from the Poros centre. Equally, in the absence of inspections by human rights bodies, we are unaware of the standards of hygiene inside the facilities, or if there is sufficient food available. Administrative acts archived in diavgeia.gov.gr normally offer some answers to such questions but, as we mentioned above, we could find none. In short, it appears that Poros is used as an informal detention centre, hidden from public view. 7