More than a tenth of Home Office interviews of gay and lesbian asylum seekers include “intrusive or unsatisfactory” questions about their sex lives, according to an investigation by the chief inspector of borders and immigration.

John Vine said the Home Office must eradicate unacceptable questioning in asylum interviews that query the validity of same-sex relationships or were likely to elicit sexually explicit responses.

The chief inspector cited examples of unsatisfactory questions that included asking why a gay asylum seeker felt the need to have sex every day when that was “not even normal in heterosexual relationships”.

In another case, an asylum seeker was aksed whether he had had “less than 100” sexual partners before his current boyfriend. In a third case, a gay asylum seeker was asked what a relationship with a man could provide that was absent from a hetreosexual partnership.

Vine was asked by the home secretary, Theresa May, to investigate the handling of gay and lesbian asylum claims after the Observer published extracts of an asylum interview this year, in which a Home Office caseworker had asked sexually explicit questions.

“None of the interviews in our sample contained sexually explicit questions of the type highlighted in the Observer article. We did, however, find some questions which, we considered, invited applicants to give sexually explicit responses that were likely to be irrelevant to their asylum claims,” said Vine.

“Other questions were either not relevant or appeared to be formulated to make claimants feel uncomfortable, for example by implying their sexual orientation was a deviance from a heterosexual norm.”

Vine said of the 112 interviews of gay and lesbian asylum seekers his investigation reviewed, about 12 or about 10% included intrusive or unsatisfactory questions. He said such questions were twice as likely to be asked in cases involving those who had been detained as part of the fast-track asylum process.

He said there was clear Home Office guidance emphasising that sexually explicit questions such as: ‘Did you put your penis into X’s backside?’, cited in the Observer article were never acceptable.

In a series of three reports published on Thursday, Vine also criticises UK Border Agency staff for failing to act quickly enough on tipoffs from the public and the police and missing opportunities to tackle immigration offenders.

He said progress had been made since his previous report, in 2011, which criticised the lack of action taken on tipoffs. He said since then an intelligence management system had been developed. More than 75,000 allegations were added to the system in 2013, which led to more than 4,000 arrests and 1,000 removals.

However, he also found immigration staff were failing to act promptly on 39% of the tipoffs in which they had taken more than two working days, the target set by ministers, to process the allegations. “This led to some time-critical allegations not being assessed until it was too late to take preventative action,” he reported.

A home office spokesperson said they had accepted all of the Vine report’s recommendations, including ensuring sexually explicit questions were not asked.

“We are putting in place measures to implement,” she said.

“The UK has a proud history of granting asylum to those who seek refuge by establishing a genuine need for protection. The chief inspector praised our guidance and training on handling sexual orientation claims, stating that it was clear and concise. We worked closely with organisations such as Stonewall, the UK Lesbian and Gay Immigration Group and the UN High Commissioner for Refugees to develop this training, which is now mandatory for all our caseworkers.”