The British asylum process is a lottery and many asylum interviews are rushed, biased and resolved by “cut and paste” decisions by overworked Home Office staff, whistleblowers have told the Guardian.

Former staff employed in deciding asylum claims said some colleagues had a harsh, even abusive, attitude towards applicants, mocking them to one another and employing “intimidation tactics” during interviews.

As a result, the whistleblowers said, the asylum system was in effect a lottery, depending on the personal views of the decision-maker who picked up the file. They said some staff took pride in rarely, if ever, granting asylum.

“I know some people that have left, they had been here a few years, [who] only did one or two grants of asylum, which in my eyes is just absurd,” said one former caseworker.

“It’s just a lottery,” said another. “Because if you’ve got a caseworker who was particularly refusal-minded and was determined to catch you out then you’re going to have a hard time … There was one particular guy who had a reputation for never granting anything. He kind of took pride in that as well. On the one occasion when he did grant someone, I think someone brought him in a cake.”

The latest revelations come a month after Home Office staff told the Guardian that the asylum directorate was in a “constant state of crisis” because of overworked staff and a huge backlog of around 50,000 cases.