Keeble, a former Northampton North MP, called for “full information” on the process.
“These vulnerable mental health patients are being failed again by health services,” she said.
“The care they received at St Andrew’s was so unsafe the NHS ordered their removal. One month on, it seems that almost all of them are still there.”
Keeble said she had also asked NHS England for the number of patients removed so far, and which health bodies they came under.
The BBC can also reveal that mental health charity Mind met Health Secretary Wes Streeting earlier this month to discuss its concerns over the future of St Andrew’s patients.
Tom Pollard, head of policy and influencing at the charity, said Streeting had “reassured us that the department is taking the situation at St Andrew’s very seriously”.
He added: “We do, however, remain concerned about wider systemic issues driving failings in inpatient care and we raised this with him.”