The Home Office has been criticised by a public-sector watchdog for huge delays and blunders over immigration cases.
More than two-thirds of complaints against the department and its agencies were upheld by the Parliamentary and Health Service Ombudsman last year.
In one case a teenager had to wait nearly 10 years to be granted permission to stay in the UK, and was paid £7,500 in compensation.
According to the report, 158 complaints were investigated about the Home Office, Border Force, UK Visas and Immigration, and Immigration Enforcement in 2014-15.
Some 69% were upheld - over double the average for the public sector.
Delays and poor decision-making were the most common problems.
Parliamentary and Health Service Ombudsman Julie Mellor said : "Too many people's lives have been put on hold for years by the Home Office because of delays and poor decisions.
"We have seen far too many cases where people have been separated from their loved ones, unable to work and where their children have been denied access to education.
"It is the responsibility of every board of every UK government department and agency to recognise the profound impact poor services can have on people's lives and make sure they learn from complaints to improve services for all."