The criminals use the cover of French fishing trips to avoid drones which monitor crossings.
Small boats already inflated are hidden inside the fishing boats with the migrants and released in British waters.
Evidence seen by The Sun shows fishing boats leave Calais in the early hours, make a journey across the Channel, then spend around 15 minutes “still” — before returning back.
That is said to be enough time for the dinghy or inflatable boat to be released, the migrants placed on it and then “sent on their way”.
Sources say migrants have been seen arriving just hours later either emerging directly on beaches or being brought to shore by Home Office ships.