France has been urged to do more to stop illegal Channel crossings after scores of migrants were caught sailing to Britain last weekend.There have also been calls for air surveillance of the English Channel to stop people from entering the UK illegally this summer. Border Force officials detained 74 people, including small children, after eight boats were spotted off the Kent coast on Saturday.Two vessels were also intercepted in France by the French authorities, the Home Office said. Lucy Moreton, general secretary of the Immigration Service Union, said French authorities must take tougher action to prevent migrants from leaving their country. “What happened this weekend demonstrates that the current scale of surveillance is not effective,” he added. “We need to look again at whether there should be air surveillance and also have a frank talk with the French about whether they are doing enough to stop people leaving their shores.”Home Secretary Sajid Javid said he has agreed a “joint action plan” with the French. “We will continue to seek to return anyone who has entered the UK illegally,” he said.The 74 people arrested on Saturday have since undergone medical examinations, and authorities are working to establish their nationalities.A criminal investigation has also been launched. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. She told The Times: “These people should not be setting sail from France. They are buying boats and stealing boats. We really need a lot more work on the part of France.“These people are coming from France. They should apply for asylum in France and the French authorities should process that claim.”Criminal gangs are exploiting the migrant crisis by charging up to £20,000 to bring people from Iran and Afghanistan to the UK, Ms Moreton added.Damian Collins, Conservative MP for Folkestone and Hythe, said he was “extremely worried” that current surveillance measures were not picking up small ships.