- Around 10,000 people and their dependants are not in touch with officials
- Some have not had cases decided while others are awaiting deportation
- More than 30,000 failed asylum claimants have not been removed from UK
- Failing to deal with claims in a timely way is 'inefficient' and 'ineffective'
Thousands of asylum seekers have dropped off the Government's radar and looking for them is considered by enforcement teams to be a 'drain on resources', the borders watchdog said.
Inspectors have been told the Home Office has lost track of or is not in touch with 10,000 claimants and their dependants, such as children.
Some of the group are still awaiting a decision on their asylum claims while others are still in the country after their application has been refused.
David Cameron and Theresa May met Home Office Immigration Enforcement officers last year. The latest Government figures suggest some 30,000 failed asylum seekers are still in the UK
While enforcement teams could conduct residential visits to attempt to trace missing claimants they were 'reluctant to do so as this work was not a priority and was considered a drain on resources', a report by the borders watchdog said.
The Home Office prioritises catching foreign criminals and uses a series of tactics including adding people to the police national computer.
It was also disclosed that, as of September last year, there were more than 30,000 failed asylum claims where individuals had not been removed from the country or given leave to stay more than two years after their right of appeal had lapsed or been exhausted.
A report by the chief inspector of borders and immigration David Bolt said: 'Failure to deal with asylum cases in a timely manner was inefficient as well as ineffective.
'The more time an asylum case took to resolve, the more likely barriers to removal would arise from the formation of relationships, the birth of children and other community ties.
'It also meant individuals were left not knowing if or when the Home Office might take action to remove them.'
In its response to Mr Bolt's report, the Home Office said: 'The Home Office is committed to preventing absconding and locating absconders in line with their level of harm and other strategic priorities.
'We have already commenced a review of approach and related guidance in this area, in addition to the hostile environment making it far less attractive for absconders to remain in the UK illegally.'
Immigrants who are required to report to officials are recorded to have absconded when they fail to attend.
In a sample of 338 cases examined by inspectors, 48 individuals were logged as absconders.
Of these, an attempt to locate the person had been made in only nine instances, including five in which teams visited last known addresses.
On the 39 occasions where no attempt was made to trace the immigrant, six records indicated this was because of resources or because the case did not meet priorities at the time. In the other 33 cases, no explanation was recorded.
Mrs May has been criticised for anti-immigration rhetoric following her party conference speech but the Home Secretary has insisted she is right to acknowledge public concern about the issue
Staff at sites which some immigrants are required to attend periodically said their resources have become increasingly stretched due to the number of individuals on reporting regimes, which stood at 47,000 last December.
The report said: 'Managers said that the numbers reporting placed pressure on back office administrative functions, such as taking action against individuals who had failed to report.'
It added that limited bed space in detention centres meant some individuals who had repeatedly failed to abide by the rules were not pursued or detained because they did not fit 'priority categories', with some of those later absconding.
The inquiry identified a 'disconnect' between the work of different departments, saying poor communication was having an 'adverse impact on efficiency and effectiveness'.
However, the report said increases in the numbers of voluntary departures suggested the Home Office's focus on this area was having an impact.