Allegations of poor patient care at two Greater Manchester hospitals are to be investigated by a regulator.
Channel 4's Dispatches programme makes claims about treatment of patients and staffing levels at North Manchester General and Royal Oldham hospitals.
Pennine Acute NHS Trust, which runs the hospitals, denies the allegations and has asked the Care Quality Commission to issue an independent judgement.
Channel 4 said secret filming took place at the hospitals.
Two reporters went undercover from December 2010 to March this year.
'Disturbed and concerned'
The Care Quality Commission (CQC) previously carried out an inspection of the trust in January where it found the hospitals to be of a "uniformly high standard".
A trust spokesman said it denied all allegations and that its lawyers were examining the claims made in the programme called, Undercover Hospital, and that it was considering legal action.
He said: "Patients and staff were secretly filmed and we are not sure that the consent of anybody featured in the programme has been sought."
A Channel 4 spokesman said people featured in the programme had their faces blurred in order that they could not be identified.
Trust chief executive John Saxby said: "We are disturbed and concerned at the wholly unspecific assertions made.
"In particular, we do not accept the unfounded, unsubstantiated and very serious allegations that patient care is being compromised to meet targets."
The programme is due to be broadcast on Monday evening.