A former judge has warned there will be “no place for obstruction or foot dragging” as he opened an inquiry into the Channel’s deadliest migrant crossings tragedy on record.

Sir Ross Cranston said the purpose of the independent probe – announced by Transport Secretary Mark Harper in January – was to find out the “truth” of what happened when at least 27 people died as an inflatable boat capsized while attempting the journey to the UK on November 24 2021.

The inquiry chairman, an ex-High Court judge and former solicitor general, told a hearing in London on Wednesday the proceedings would ascertain who the people who died were, and when, where, and in what circumstances they came to their deaths, as well as considering “what lessons can be learned” from the incident and what recommendations could be made to “reduce the risk of a similar event occurring”.

This will include considering whether suggesting improvements “in search and rescue practice ought to be made for the benefit of all those who use these commercially important waters between France and the United Kingdom”.

Sir Ross, who represented Dudley North as a Labour MP between 1997 and 2005, said: “All of those who engage with our work must do so on the clear understanding that there is but one purpose to the whole exercise, to find out the truth.

“Their task is to assist the inquiry in its investigation and in getting to the truth of what happened.

“To that end, I hope and expect to receive full co-operation from all of those involved in our work.

“There’ll be no place for obstruction or foot dragging on the part of those whose involvement in the events of November 24 2021 will be scrutinised.

“This is of vital importance if the work of the inquiry is to proceed in an efficient and effective way.”

A report by the Marine Accident Investigation Branch (MAIB) published in November last year found the capsized boat was “wholly unsuitable and ill-equipped” for the crossing, adding that the UK’s search and rescue response was hampered by the lack of a dedicated aircraft carrying out surveillance.

A pregnant woman and three children were among the victims when a boat which appeared “wholly unsuited to the voyage took on water and was swamped” but there were “remarkably two survivors”, Sir Ross said.

“It was, and remains, the single greatest loss of life occasioned by any of the small boat crossings,” he added.

Describing Channel crossings as a “politically controversial issue with significant humanitarian consequences”, he stressed the focus of the inquiry was not on those “complex issues”, had “no remit to investigate the general problem of small boat crossings” and cannot become “a vehicle for wider debates” as he vowed: “We will not lose sight of the fact that … this was, above all, an immeasurable human tragedy.”

Phillippa Kaufmann KC, who represents one of the survivors of the “catastrophic” incident and the families of 20 of the people who died, said they “wholeheartedly welcome” the opening of the inquiry, adding that it was “something they fought hard to establish” and having “endured a long and painful wait of 27 months” were grateful for the commitment from Sir Ross to carry out a “prompt and thorough investigation”.

She told the hearing: “Our clients have high hopes for this inquiry.

“They hope that it is going to establish the truth as to what happened and how it is that such a significant loss of life occurred. And as part of that, they hope that insofar as they were failed by any authority tasked with planning, search and rescue operations that night in the Channel, that those will be identified and explained.

“And finally, they hope that lessons will be learned that can help prevent such a terrible loss of life in the future.”

James Maxwell-Scott KC, representing the Maritime and Coastguard Agency (MCA) – which is part of the Department for Transport but has operational independence for sea rescues, said the body would do “all that it can to assist the inquiry” as he sought to highlight how it abides by international legal obligations to help people found in distress at sea.

“It does not matter whether they are in the course of a commercial voyage, a recreational voyage or a clandestine voyage. It does not matter whether or not they have a legal right to enter their intended destination,” he said.

The “phenomenon” of Channel crossings – with numbers “rapidly” increasing in recent years after just nine incidents were recorded by the Home Office between July 2014 and May 2016 – had “given rise to new and distinct challenges” and while search and rescue procedures had “necessarily had to evolve”, the coastguard’s role had stayed the same.

“It is, and always has been, to respond to those in distress and to treat all persons at sea equally,” Mr Maxwell-Scott added.

The Home Office’s barrister Prashant Popat KC said the department wished to “express its profound sorrow” in the wake of the incident and hopes the inquiry brings some degree of “solace” to the survivors and families of those who died.

“The Home Office is committed to cooperating with, and supporting, the inquiry in its investigation and will consider carefully any relevant recommendations that arise from the inquiry’s review”. The department’s response “has always been guided by the preservation of life”, he said.

The inquiry’s findings “will materially contribute to the goal of stopping these criminal gangs from putting so many people in such perilous situations so that such a tragedy never happens again” Mr Popat added.

While David Blundell KC said the Department for Transport “stands ready to support it in whatever ways it can in seeking to understand both what happened in that tragedy, and what can be learned from it.”

Issuing a call for evidence, the inquiry – which does not have the same legal powers as a statutory probe – will now consider the information it receives before public hearings take place at a later date. But no timescale has yet been set.

Sir Ross said he would report his findings to the Transport Secretary “as soon as practicable”.