A Polish man was found dead at Morton Hall detention centre in Lincolnshire on Wednesday morning of last week.
Fellow detainees told solidarity campaign The Unity Centre that he was distraught after being refused bail to see the birth of his child.
It is the second death at Morton Hall in little more than a month.
Detainees say mental health support is poor, and that another man is in hospital after stabbing himself.
It has prompted calls for better levels of health care and mental health support for detainees.
The centre is a former prison and still run by the prison service.
But unlike prisoners with sentences to serve, migrants are detained indefinitely and cannot even have a release date to look forward to.
European Union nationals can be detained if they have committed a crime in the past.
From last year the police and Home Office “Operation Nexus” have sought to round up migrants suspected, but not necessarily convicted, of past criminality.
Detainees held a self-organised memorial inside Morton Hall, attended by all those in the dead man’s wing.
The Unity Centre held a protest outside a branch of the Home Office in Glasgow on Monday.
Shame of deaths at sea
Around 100 people are believed to have died 30 miles off the coast of Libya when their boat to Italy sank last Saturday. Hundreds more migrants were rescued from overcrowded boats.
Crossing the Mediterranean illegally is dangerous enough in summer. But this is the second year running in which crossings have continued in treacherous winter conditions.
A clampdown on fishing boats by the European Union and Nato—including British ships—has driven people to use inflatable dinghies.
A Somali man died last Thursday night in a fire at a reception centre in Florence, Italy. Angry refugees took to the streets. It follows protests in Bologna over the death of a woman from Ivory Coast.
A record 361,678 migrants arrived in Italy last year. Most are still trapped there.
However, French rail company SNCF has met resistance from workers who refuse to police migrants crossing the Italian border.
Some train guards openly refused to “rat” on refugees or join in a “migrant hunt”.