Staff in the Home Office’s asylum directorate are undertrained, overworked and operating in a “constant state of crisis”, two whistleblowers have claimed, as applicants endure long waits to have their case dealt with due to internal pressures.

The Home Office staff have also told the Guardian that asylum case workers are making poor decisions about applications because they are under pressure to focus on more profitable visa applications. Despite a “shocking increase in complaints (from applicants) and MP enquiries questioning delays”, they say caseworkers have been told to brush off all enquires and “just give standard lines” of response when called to account.

A source from the UK Visa and Immigration Unit (UKVI) has alleged that caseworkers have been ordered to kick applications for spousal visas “into the long grass” because they can make more money for the directorate by processing student visas. Spousal visas, also known as settlement visas, cost more than student visas but take much longer to process.

The source also claims visa applications are routinely labelled “complex” or ”non-straightforward” by staff – a term which excuses the UKVI from adhering to their standard processing times – it is, the source claimed, “just a euphemism for ‘there’s more profitable stuff we could be doing’”. Paying hundreds of pounds for priority services to try to avoid delays on decisions is a “waste of time”, they warned applicants.

The allegations reflect concerns expressed in a report earlier this year by David Bolt, the Independent Chief Inspector of Borders and Immigration, who said the Home Office is not “in effective control” of its asylum process.

In his damning independent inspection report, Bolt said that unless the Asylum Intake and Casework (AIC) unit accelerates its plans to resolve its “struggles” to keep on top of immigration claims, the unit will soon “be unable to cope”. But those plans, he added, are currently “not sufficiently advanced”.

Some of the more shocking findings from Bolt’s report included pregnant women being made to wait more than two years for decisions on their immigration applications; an increasing numbers of applicants having their immigration applications registered as “not straightforward” and endlessly delayed; and Home Office employees being “pushed to the limit” by individual targets and threatened with disciplinary action as deadlines approach.

Bolt’s report revealed that in 2016 to 2017, the number of claims categorised as ”non-straightforward” peaked in March this year, representing almost half of the initial case assessments.

The independent report expressed concern that of the non-straightforward cases in March, more than half were over 12 months old and less than one-quarter had been reviewed. “This is in direct violation of the Home Office’s internal performance aims, whereby non-straightforward cases should be cleared in 12 months and the claimant kept informed of progress,” it said.

The report was sent to Amber Rudd, the home secretary, on 25 September and published in November.

The source also said that mistakes are being made by caseworkers when they decide whether applications are denied or accepted, because they have targets for the number of cases they must deal with each day. “Caseworkers don’t have time to request more documents if something is missing or if more information is needed,” they said. “Sometimes they don’t even have time to read the applications properly.”

The Home Office has suffered 24.9% cuts to its £10.6bn annual budget and has been asked to outline potential additional spending cuts of 6%. It strongly denies that financial incentives influence its immigration decisions.

The second whistleblower comes from inside the Family and Human Rights Unit (FHRU), a department inside the UKVI which focuses on visas for spouses and parents of British and EU nationals. They describe a similar state of constant crisis: “We currently have staff who are trained for one week before doing live cases. There is a high turnover (in the unit), staff are leaving and coming every week,” they said.

FHRU cases are streamed into three tiers according to their complexity, but junior administrators are regularly given more complex cases reserved for managers, the source said.

“Caseworkers will make poor decisions because of lack of training, support and mentoring from experienced caseworkers. This in turns creates a bigger workload for post-decision casework,” they said.

The backlog, said the source, is enormous. “We have 49,000 works in progress, which our senior management team has committed to get down to 12,000 by April 2018. There is currently up to an 18-month delay on FHRU cases, because they are not subject to a service standard,” they added.

“On my team, we are seeing a shocking increase of complaints and MP enquiries questioning the delay. We are just told to give standard lines.”

Mike Jones, Group Secretary for PCS, the union for Home Office employees, has canvassed his members and has found both whistleblowers’ comments to be “correct”.

“PCS have repeatedly raised concerns with the Home Office around a lack of staffing and resources within caseworking areas,” he said. “We are already seeing excessive amounts of overtime being worked due to insufficient staff to deal with work volumes.”

The Home Office has disputed the claims of both whistleblowers. Regarding the UKVI allegations, a spokesperson said: “Each application is dealt with on its individual merits. Standard overseas visa applications are prioritised on the facts of the case and not based on profit.”

Regarding the FRHU allegations, a spokesperson said: “We do not recognise these claims. We have dedicated and hardworking staff who are prepared to go the extra mile to provide a high level of service with what are often complex applications. Their individual workload is appropriate and dependant on their seniority and experience.”