Helplines run by government agencies are often slow to pick up and some do not answer as many as half of calls, the BBC has learned.
The waiting time for a phone call to the UK Border Agency is almost seven minutes and then 70% of calls are abandoned or go unanswered.
Three other Home Office helplines were among the worst contacted, Freedom of Information requests also revealed.
The Home Office said it was working to improve access via online services.
The contact centre for work permits took five minutes on average to answer a call.
The nationality contact centre also took five minutes, while the asylum support centre took three minutes.
'Doubled call demand'
About half of calls inquiring about work permits and asylum support were then disconnected.
A Home Office spokesperson said: "Since 2007, call demand has more than doubled, which has had an impact on our call times.
"We have already begun to address this by moving more of our services online, including the booking of appointments.
"This provides easy and quick access to a lot of the information that is needed and allows our staff to focus on the inquiries that require telephone assistance."
The Student Loans Company, which came under fire last year for a backlog of claims, was unable to answer almost three out of five calls - and students who did get through, faced a four-minute wait.
The company said it had been its "busiest and most challenging academic year to date".
This year it has pledged to take on more staff, and a spokeswoman said: "We aim to answer at least 80% of calls to ensure students can get the information they need."
Driving pupils trying to book a theory test through the Driving Standards Agency's helpline faced a six-minute wait in 2009.
The agency said it worked hard to make sure customers could get in touch quickly and easily.
"The maximum waiting time listed would only apply if a caller listened to every available message - in practice, most people contact the number to book a car theory test and this is the first option given," it said.
The Give Blood and Organ Donor line was found to have improved in the past year.
The number of calls it handled increased, but waiting time was reduced to just nine seconds.
It is all but impossible to get through and then all but impossible to get any sense out of the person at the other end if you do. The booking line for making further representations in Liverpool is said to be far and away the worst. I’ve heard horror stories of literally hundreds of attempts to get through, meticulously documented in the vain hope of persuading UKBA to make improvements.UK Visa Works comments:
The worst bit is that most of the numbers are 0870 or 084 for which you are normally charged more than calls to 01 or 02 numbers.