Some 400 Irish people emigrate to Britain in crisis situations every year, according to a migrant support group.
Crosscare Migrant Project, formerly Emigrant Advice, says its research and feedback from Irish organisations in Britain suggest about 400 of the 4,000 Irish people who emigrate to Britain every year find themselves in situations of "extreme vulnerability and crisis".
They include the homeless, people with addiction or mental health problems, those fleeing threats of violence and others who have just left prison.
"On a monthly basis, we get reports from Irish housing and welfare organisations in places like London, Liverpool, Manchester and Birmingham of Irish people presenting to their service in situations of extreme vulnerability and crisis.
"Some people still end up homeless on the streets due to lack of support and preparations before they go to the UK," said Crosscare's Paula Lally.
She was speaking at the launch of four pre-departure information booklets for emigrants to Britain, the United States, Canada and Australia. The latter three are aimed at skilled migrants going for better jobs, for lifestyle reasons or to join family members, but the booklet for Britain is directed mainly at the vulnerable.
It advises intending emigrants to buy a return ferry ticket and to bring photographic ID and a long-form birth certificate with them. Without these documents, new arrivals in Britain cannot apply for a national insurance number, which is required to access emergency accommodation, benefits and other services.
Crosscare co-ordinator Yvonne Fleming said that while the number of emigrants had declined and attention was turning to the needs of immigrants, "it's important to remember that there are still Irish people who are leaving, and proper preparation is as important as ever for everyone, whether they are coming here or going abroad.".
The booklets, which are free of charge, will be distributed to libraries, citizen information centres and other agencies.