Capita tells departed migrants to leave UK
Foreign workers have been told to leave the country by a firm working for the Home Office, even though they went back to India four years ago.
Thirty-one migrants who have previously left the UK were incorrectly told to leave by Capita this week.
The firm was contracted by the UK Border Agency (UKBA) in September to track down 174,000 illegal immigrants.
The Home Office says it is "vital" to contact those who records show are here illegally.
The BBC has previously revealed how some legal migrants living in the UK had also been told to leave.
Capita says part of its job is to "identify those whose records suggest they are overstayers but who have already left the UK".
The contract could be worth up to £40m for Capita, which is one of the largest contractors working on outsourced local and national government operations.
But Adrian Farley, an immigration adviser, has told BBC News that he received letters on Thursday for 31 of his clients demanding that they go back to India.
They were all IT specialists who had been on short term work contracts providing services to a UK company.
The letters state: "You no longer have the right to remain in the United Kingdom" and that "you must make immediate arrangements to leave the United Kingdom and provide proof you have done so".
But they had all left Britain in 2008, Mr Farley said.
"We had to notify the UKBA, we did so in October 2008 and again in June 2009, clearly stating that each individual had gone home.
"My concern is how the information is being shared, where Capita has been given this list of individuals from I do not know. It's the right hand not knowing what the left has done or is doing."
He said his experience calls into question the accuracy of the government's figures on illegal immigrants.
"I've got 31 illegal migrants, that aren't in the UK but are overseas. Who's to say exactly how many people are here illegally when they're not?"
A spokesman for Capita said: "Part of Capita's role is to identify those whose records suggest they are overstayers but who have already left the UK.
"If we receive evidence to indicate that an individual has valid leave or has left the UK then records will be updated accordingly."
The Home Office said: "Where our records show that people are here illegally, it is vital we are able to contact them as we are determined that they should return home."
Earlier this week, BBC News revealed that people with valid visas were being contacted in error and told to leave the UK.
Among those contacted by text and email were a woman with a UK passport, and a man with a valid visa who had invested £1m in a UK business.
Migrants are contacted by text message, telephone or email.
The standard text message reads: "Message from the UK Border Agency. You are required to leave the UK as you no longer have the right to remain." It then advises people to contact the agency.
The UKBA admitted last year that it could not locate the 174,000 people from the Migration Refusal Pool, whose applications to stay in the UK had been refused.
It was also revealed that about 60% of them had never been served with documents requiring them to leave the country.
Capita was hired to trace those in the pool and warn them that they are required to leave the country. The firm will be paid depending on how many actually go back to their home country.
A UKBA spokesperson said: "This is the first time a government has taken proactive steps to deal with this pool of cases, some of which date back to December 2008.
"We have to make sure we keep control over our immigration system and we will enforce the removal of anyone who refuses to go home voluntarily."