Twice as many Albanians have been caught as stowaways at British ports than any other nationality, government figures have revealed.

981 Albanian “clandestine migrants” were caught at UK entry points between 2008 and the spring of 2016, according to a Freedom of Information request to the Home Office lodged by The Guardian.

Afghans made up the second largest cohort, with 425 caught during the same period, followed by Algerians (424), Iranians (348), Indians (322), Palestinians (129), and Vietnamese (124).

One U.S. passport holder was intercepted during the period, as well as one from Russia and another from the Czech Republic, which is inside the European Union’s free movement area – although passage can be barred to serious criminals.

As the migrant crisis took hold in 2015, there was a notable increase in Iranians, Syrians, and Iraqis caught at Britain’s borders. During the first three months of 2016, the latest period for which figures are available, 122 Iranians, 31 Syrians, and 21 Iraqis were intercepted at British ports. In the same period, 318 illegal immigrants were found in total – compared with 556 in the whole of 2015, and 681 in 2014.

However, most illegal immigrants are intercepted trying to board transports bound for the UK, rather than on UK soil. An FoI request lodged by the Economist last year showed the number of migrants caught attempting to enter Britain via European ports and train tunnels rose from about 1,000 a month in 2008-12 to 2,000 in late 2013, before increasing rapidly to 4,000 by 2014, and almost 13,000 in July 2015.

The information was reluctantly released by the Home Office, who only handed over the figures after being ordered to do so by the Information Commissioner.

A request to detail which ports the illegal migrants were detained at was refused “on the grounds that release would or would be likely to, prejudice the operation of the immigration controls”.