Long lines of tourists and vehicles formed outside the Port of Dover, Britain’s major entrance to Europe, on Saturday, and officials warned that the disruption might be greater than the one experienced on Friday.

Travellers beginning their summer vacations in the United Kingdom, as well as the typical flow of cargo vehicles, have experienced lengthy waits due to delayed border procedures.

The Kent Resilience Forum, which includes local governments and emergency services, declared a “serious crisis,” and Port of Dover CEO Doug Bannister warned that travelers might face up to six-hour delays on Saturday.