It featured four new revelations:

That the billion plus items of Personal Protective Equipment (PPE) that the government has supplied included cleaning products and individually counted gloves, which is sourced from a document tracking national PPE supply.

That gowns, visors, swabs and body bags were not included in the pandemic stockpile. Last year expert advisory committee NERVTAG (The New and Emerging Respiratory Virus Threats Advisory Group) recommended gowns be added to that stockpile but they were not. This is sourced from NERVTAG minutes. The lack of any gowns, visors, swabs and body bags in the stockpile was confirmed by Public Health England.

That although 33 million FFP3 respirator masks were specified in the stockpile procurement list, only 12 million have been distributed. The programme sought, but received no explanation from the Department of Health and Social Care (DHSC) for what happened to the other 21 million.

That steps to remove Covid-19 from the High Consequence Infectious Diseases (HCID) list were taken by the DHSC on 13 March, the same day PPE guidance was downgraded. Sources on the committee who supported the removal of Covid-19 from the HCID list told Panorama the decision to remove it was in part based on how much PPE was available.

The sources for the new revelations were not the doctors who appeared in the programme.

We were in regular contact with DHSC to give them the opportunity to respond and we included responses from the Government throughout the programme.

The programme spoke to a range of interviewees, including public health policy experts, and those involved in the supply of PPE. Where it was relevant, we indicated that they had been vocally critical of the Government.

We also wanted to include the personal experiences of doctors and nurses who are risking their lives to treat Covid-19. More than 100 NHS and other healthcare workers are known to have died with Covid-19 to date. Some of those interviewed are members of a political party and some are not. We believe that if the doctors featured in Panorama feel their lives are at risk due to lack of proper PPE it is valid, and indeed in the public interest, for them to reflect on that experience, regardless of the political views they may or may not hold.

Some NHS Trusts have discouraged health care workers from discussing the lack of PPE. So it is perhaps not surprising that those willing to speak out are more involved with campaigning around the NHS. We did signpost that issue in the programme - highlighting how few are willing to speak out. We spoke to dozens of health care workers during the making of the programme and they all had concerns about the shortage of PPE. These concerns have also been reflected by the BMA and the Royal Colleges.

We speak to a wide range of people in the course of our journalism. However, with the exception of a nurse who we identified as a union representative, none of the interviewees were sourced through trade unions.

There have also been social media allegations that the BBC ‘held back publicity’ for this programme. This is not the case. The programme was not finished until Monday afternoon. The BBC then issued a press release detailing its findings. They were covered on the News at Six (the BBC’s most-watched bulletin), and the News at Ten that evening, were written up on the BBC News website, and were put to the government minister interviewed on the next morning’s Today programme and BBC Breakfast.