LONDON: The UK’s Marine Accident Investigation Branch is looking into the response by British authorities to a boat carrying migrants that sank in December with the loss of at least four lives.

Concerns had been raised about the speed with which emergency services responded to distress calls from the passengers, who included teenagers and unaccompanied children.

A charity initially contacted the French coastguard after receiving a message from a passenger pleading for help, the Independent newspaper reported. “We are in a boat, we have a problem. Please help us. There are children and families in the boat, water is coming in from the back. We are in the water,” the caller said.

French authorities said they quickly determined the vessel was entering British waters. They alerted UK coastguards in Dover and “gave full support and assistance to the British authorities.”

Officials estimated that the boat entered British waters at around 2:30 a.m. Shortly after 3 a.m., a passing fishing vessel spotted the sinking boat and began to pull people from the water.

Its captain told the Independent that he saw “people in the water everywhere, screaming” and his crew scrambled to save as many people as they could.

The British government has said the UK search and rescue operation began at 2:16 a.m. but confirmed that the fishing boat was the first vessel to arrive at the scene. It added that 39 people were rescued from the water, but four people died.

Following years of increasing numbers of small boats crossing the English Channel, the British government has been accused of putting lives at risk by failing to establish safer, legal routes for asylum seekers to reach the UK.

“The focus of the investigation will be on the UK’s emergency response, a MAIB spokesperson told the Independent.

“The mechanism for the foundering of the small boat will also be explored.”