The data used on this site is taken from the government's official daily summary of small boat crossings and weekly summary data. This is retrieved daily, usually about 30 minutes after the government website is updated.
The government publishes data for daily and weekly crossings. This website also aggregates the daily figures into monthly figures, as these give a better indication of long-term trends. Daily and weekly figures can be very variable, as they are strongly influenced by external conditions such as the weather and the success of the French authorities in preventing departures. Even at the busiest times of the year - typically, the summer months - there will often be days with no crossings. Weekly and monthly figures are more useful for seeing a long-term pattern.
For the monthly figures, this site also shows an average number of migrants per boat. This is calculated from the number of boats and number of migrants. Figures may not tally precisely due to rounding and updated provisional data.
This site also includes a rolling year-on-year comparison, which goves a quick visual indication of how numbers compare across different years.
These statistics are taken from provisional UK and French operational data and are subject to change. They may differ from figures published in the official immigration statistics, which will have undergone a more thorough quality check.
The following definitions are used by the government:
A 'small boat' is one of a number of vessels used by individuals who cross the English Channel, with the aim of gaining entry to the UK without a visa or permission to enter - either directly by landing in the UK or having been intercepted at sea by the authorities and brought ashore. The most common small vessels detected making these types of crossings are rigid-hulled inflatable boats (RHIBs), dinghies and kayaks.
Data on preventions are operational estimates collected and provided to the UK by French authorities.
The data on preventions does not include: