Diane Abbott has called for a "safe and legal routes" for refugees to enter the UK after 39 people were found dead in a lorry in Essex.
The Shadow Home Secretary made the call after police launched a murder probe into the deaths of after the bodies were discovered in the early hours of Wednesday morning.
The Labour front bencher said: "Any death under these circumstances is truly appalling.
"The fact there have been 39 reported deaths in this incident is a terrible tragedy. One of the worst of its kind."
The unidentified victims, including a teenager, were found dead inside the container - thought by experts to be a refrigerated unit - at the Waterglade Industrial Park in Grays, Essex, early on Wednesday.
Police said the lorry driver, a 25-year-old man from Northern Ireland, has been arrested on suspicion of murder.
The lorry is from Bulgaria and entered the UK at Holyhead in North Wales, one of the main ports for ferries from Ireland.
Police have not confirmed if the dead were trafficked into the UK or had intended to claim refuge here, but their death has highlighted the ongoing issue of desperate people dying trying to reach safety in the UK
Ms Abbott added: "These 39 poor unfortunate people are the victims in this. They are preyed upon by the greedy, unscrupulous and people who simply have a willful disregard for the lives of others.
"But we should take account of the wider context. Nobody leaves their homes on a journey like this, with so much risk and fear, on a whim. They often do it because they are actually desperate."
She called for an assurance that "vital" co-operation on preventing people trafficking with the EU27 will not become "imperiled" when the UK leaves the EU.
She said there should be "safe and legal routes" for "genuine" refugees to get to the UK.
Home Secretary Priti Patel said there would always be "international co-operation" and collaboration with EU countries and others around the world to prevent illegal human trafficking.
She said the UK has to "do the right thing as a country" to uphold the "right kind of values".
She said this means making sure people fleeing war zones and conflicts are given asylum "in the right way".
It came after Jeremy Corbyn asked MPs to consider the "desperate situation" which led people to risk their lives.
The Labour leader told MPs: "We should think for a moment of what inhumanity is done to other human beings at this terrible moment."
Mr Corbyn paid tribute to the emergency services who are dealing with the discovery, after police launched murder probe into the incident.
The Prime Minister said the perpetrators of the crime "should be hunted down and brought to justice".
During PMQs , Thurrock MP Jackie Doyle-Price said: "To put 39 people into a locked metal container shows a contempt for human life that is evil. The best thing we can do in memory of those victims is to find the perpetrators and bring them to justice."
It came as Amnesty International said the incident highlighted the failure of the UK's immigration policies.
Amnesty's Steve Valdez-Symonds said: “This is a heartbreaking and horrifying incident.
"People who are forced to take dangerous and sometimes fatal passages to reach the UK often do so because current immigration policies and practices deny them safe and legal options."