The UK is to deploy two extra Border Force ships to the English Channel to try to disrupt a recent increase in people trying to reach the UK from France in small and often unseaworthy boats, Sajid Javid has announced.

The home secretary said two Border Force cutters would be moved as part of wider efforts to ensure the route does not become more popular in response to several days of headlines about a rise in the still relatively tiny number of people attempting the crossing.

The two cutters, the Border Force’s biggest class of patrol boats, had been working with Greek authorities on anti-people smuggling and rescue operations in the Aegean. They will join another cutter and two other patrol vessels already in the Channel.

Javid, who cut short a family holiday in South Africa to return to the UK to deal with what he has officially designated a “major incident”, said the redeployment was about trying to secure borders and prevent deaths among those making the trip.

“When it comes to human life, clearly I want to make sure we are doing all we can to protect people, and we must remember that this is one of the most treacherous stretches of water that there is – 21 miles, people taking grave risks,” Javid told Sky News after he chaired a meeting of the Border Force, National Crime Agency and other government departments and agencies.

On Monday morning a group of 12 people who said they were Iranian, including two women and a 10-year-old, were taken in by Border Force officials after landing at a beach in Greatstone, near Romney in Kent, in a black dinghy.

A number of Iranian nationals have been among the 220-plus people believed to have attempted such a journey in the past six weeks. It is believed the increased numbers attempting the crossing is due to tougher security around ports and the Channel tunnel, and worsening conditions for them in northern France.

Javid said the new patrol vessels would be part of “action on many fronts” to try to deter people. This will also include stronger law enforcement with the French, new efforts to disrupt attempted crossings and measures to ensure more of those who make the trip are returned to France.

The initiatives follow a phone call on Sunday between Javid and the French interior minister, Christophe Castaner.

Javid said: “I want to send a very strong signal to people who do think about making this journey – we will do everything we can to make sure it is not a success, in the sense that I don’t want people to think that if they leave a safe country like France that they can get to Britain and just get to stay.”

Asked whether the numbers involved merited the response, Javid said: “Some people say, these aren’t huge numbers, but let’s also remember that our job here is to make sure this doesn’t turn into a new route for ever-increased illegal migration, so I want to stop it now as much as I possibly can.”

The home secretary has in recent days referred several times to the people making the trip as “illegal” migrants, even though it is not against the law to seek asylum in a country. Asked about his use of the term by Sky, he did not answer the question. There was no response from the Home Office when it was asked for clarification.

The Labour leader, Jeremy Corbyn, has urged a more compassionate response, saying the UK has “a duty to reach out the hand of humanity, support and friendship to people who are in danger and seeking a place of safety”.

The chief executive of the British Red Cross, Mike Adamson, urged the government to provide people with “safe alternatives” to risking the Channel crossing.

He said: “People only attempt perilous journeys like crossing the Channel because they are desperate. It is deeply concerning that men, women and children feel they have no choice but to put their lives at risk in their search for a safe place to live.”

Downing Street has backed the home secretary’s response following anonymous briefings that Javid should not have been so far away from the UK at Christmas. Asked if Theresa May asked him to return from South Africa, the prime minister’s spokeswoman said: “No. He returned to ensure he was leading the government’s response to this issue.”

Asked if this was a crisis, she added: “As the home secretary has himself said, we’ve seen a sharp increase in the number of migrants attempting to cross the Channel in small boats, and that’s deeply concerning. And it’s right that relevant government departments, led by the Home Office, should be doing all that they can do to address it.”