The Government has been accused of being "cruel and inhumane" over its treatment of the Windrush generation, who came to the UK from the Commonwealth 70 years ago.
A cross-party group of 140 MPs has written to Theresa May asking her to address concerns from the Windrush generation about their immigration status.
- What is the Windrush Generation?
The Windrush Generation are people from the Caribbean who were invited to help rebuild the UK in the decades following World War II.
In June 1948, 492 passengers arrived at Tilbury Dock, Essex, on the SS Empire Windrush after making the 8,000 mile voyage from Jamaica, Trinidad and Tobago and other islands, to the UK.
The passengers, many ex-servicemen who fought with the UK in the war, had been invited to assist with labour shortages and very few intended to stay for long.
Many simply wanted to visit what advertisements in their home nations called "the mother country".
The original immigrants were housed in Clapham South Deep Air Raid Shelter before being dispersed across the UK.
In the years following, more Caribbeans arrived and settled in areas already populated by their compatriots, forming large multicultural communities that have been vital in establishing what it means to be British.
Notting Hill Carnival, the first of which was in 1966, is an all inclusive celebration of Caribbean culture that symbolises the effect the Windrush generation has had on Britain.
- Why are members of the Windrush generation worried?
Recent changes to immigration law in the UK now require people to have documentation to work, rent a property or access benefits.
Some members of the Windrush generation, who have lived in the UK for over 50 years, have voiced concern over their right to remain after being unable to provide the Home Office with the right immigration papers.
Adult Windrush immigrants from the 1960s and early 1970s were usually marked with permanent right to reside stamps when they arrived, but their children were often included on their parent's passports.
The Home Office did not keep a record of those granted leave to remain, resulting in thousands of undocumented Caribbean immigrants who are now unable to prove they have the right to work in the UK because they don't have their original passports.
People without the right to work are prohibited from claiming benefits or access NHS services.
A UK government petition created earlier this month calling an amnesty for anyone who was a minor that arrived in Britain between 1948 to 1971 has raised nearly 30,000 signatures.
It needs to gather 100,000 signatures to be considered for debate in Parliament.
- Should members of the Windrush generation be worried?
An NHS worker who has lived in the UK for almost her entire life told ITV News how her rights are under threat as she was unable to provide the Home Office with the right immigration papers.
Glenda Caesar, from Hackney, travelled from Dominica to the UK with her parents at just six months old.
Despite living and working in the UK for more than 50 years, Ms Caesar lost her job of 16 years with the NHS as she was unable to provide the right documentation.
Cases like this are worrying for the Windrush generation, however several members of government have assured those with the right to be in the UK that they will not be made to leave.
International Development Secretary Penny Mordaunt told BBC Radio 4's Today programme: "People who are in that situation, there is absolutely no question of their right to remain, and their right to gain access to services such as healthcare."
The Prime Minister's official spokesman has said Mrs May was clear that "no-one with the right to be here will be made to leave".
She said: "She deeply values the contribution made by these and all Commonwealth citizens who have made a life in the UK, and is making sure the Home Office is offering the correct solution for individual situations.
"She is aware that many people are unlikely to have documents that are over 40 years old and she is clear that no-one with the right to be here will be made to leave."
Meanwhile Immigration Minister Caroline Nokes admitted to ITV News that in the past, some members of the Windrush generation had been wrongly deported.
She said: "There have been some horrendous situations which as a minister have appalled me."
She did however reassure those concerned, saying "I am determined to do going forward is to say we will have no more of this."
She added: "We want people to have confidence to come to the Home Office, we want to give them a message of reassurance, because we value these people."