The Home Office has refused to say how much it has spent operating Napier Barracks, the controversial military site being used to house asylum seekers.
Charities said the public “deserve to know the price of this inhumanity” and called for the figures to be published.
Home Secretary Priti Patel was also criticised for not having visited the site in Folkestone, Kent since it was turned into accommodation.
The disclosures came in response to a Freedom of Information (FOI) request submitted by the PA news agency.
A spokesman for the Home Secretary declined to comment, while a Home Office spokesman said “significant improvements” have been made to Napier Barracks but would not say what the overall expenditure has been.
The department said that some £500,000 has been spent on the site for improvements to the accommodation and recreational activities, but declined to detail how much had been handed to contractors.
Dating back more than 130 years, the ageing Napier Barracks was loaned to the Home Office in September 2020 and has been used to house hundreds of asylum seekers, many of whom have crossed the English Channel aboard small boats.
The Home Office was asked to detail how much had been spent on the barracks in preparation for, and since its use for, housing asylum seekers.
This was to include amounts paid to accommodation providers, contractors and sub-contractors, as well as expenditure on things such as upgrades and fixes.
However, that part of the FOI request was refused, with the department saying the information is considered to be “commercially sensitive”.
It added: “If we were to disclose the information to you, this would be likely to prejudice the commercial interests of both the Home Office and those companies with whom the Home Office enters into contracts.”
The FOI also asked how many times Ms Patel has visited Napier Barracks in that same time period, as well as minister Chris Philp.
The Home Office said that Ms Patel had not visited the site and Mr Philp had visited once.
Sile Reynolds, senior policy adviser at Freedom from Torture, said: “At a time when the Government should be investing in safe, dignified and humane housing for all people in the UK, it is wasting money on this hateful and divisive strategy.
“The public and the people who languish in the barracks deserve to know the price of this inhumanity. What does Priti Patel have to hide?”
Ms Reynolds called on the Home Secretary to visit the barracks so she can “see first-hand how her decisions have affected vulnerable people”.
“Her absence is an affront to their suffering,” she added.
Bella Sankey, director of Detention Action, said: “The quasi-detention of traumatised people at disused military barracks has been one of Priti Patel’s flagship policies, yet despite public outcry at the appalling conditions and criticism in the courts and in Parliament, we now learn she has failed to check for herself.”
She added that this was “shocking but not surprising” and also called for the expenditure figures to be released.
Shadow Home Office minister Bambos Charalambous told PA: “After a recent High Court ruling found that Napier Barracks was not fit for housing asylum seekers, it is shocking that ministers are unwilling to reveal how much they have spent on this sub-standard accommodation and how much they have paid to outside contractors.”
He said the Home Office must outline this information “immediately” so that it can be held accountable for the cost to the public purse.
A Home Office spokesman said: “During the height of an unprecedented health pandemic, to ensure asylum seekers were not left destitute, additional accommodation was required at extremely short notice.
“These sites are a temporary measure to ease pressure on the system during these unprecedented times and reduce our reliance on hotels.
“Significant improvements have been made to the site, including improved accommodation and more outdoor and recreational activities.”
They also claimed that the department’s New Plan for Immigration will “fix the broken asylum system”.
Some £500,000 has been spent on the site, including improvements to accommodation and more recreational and outdoor activities, including access to basketball, a library, prayer rooms and yoga, according to the Home Office.
The use of Napier Barracks for accommodation came despite the Home Office being warned by Public Health England that it was unsuitable, the High Court previously heard.
Ms Patel previously said the site was “Covid-compliant” and “has been from day one”.
A major outbreak ripped through the barracks, with nearly 200 people contracting the virus in the first months of 2021.
In June 2021, six asylum seekers previously housed at Napier Barracks won their legal challenge against the Government after a High Court judge found the accommodation failed to meet a minimum standard.