The threat was revealed in more than 122 pages of Department of Health files released by the Government last night which show senior department officials were fully aware of the scandal two years ago.

According to the documents on April 27, 2016, officials from the HSE’s health and wellbeing division held a meeting with the Department of Health at Hawkins House.

In a memo to the meeting, which was attended by eight senior department officials including chief medical officer Dr Tony Holohan, and four more senior HSE officials, HSE national director for health and wellbeing Dr Stephanie O’Keeffe said some “key stakeholders” had “reacted adversely to the programme communicating review findings to clinicians”.

And in a clear warning, she said at least one of the US laboratories had threatened legal action against the State if it told doctors of what was happening.

One of the contracted cytology laboratory providers has via legal representation alleged a breach of contract to challenge the right of the programme to communicate review outcomes to treating clinicians.

“Another contracted laboratory provider has expressed serious concerns, though not by legal representation, to programme management about the same matter,” Dr O’Keeffe wrote.

“The cytology laboratory in question has invoked the dispute resolution procedure in the contract and numerous legal letters have been sent by the solicitors.”

The legal threat came as HSE officials were also noting the fact neither of the US laboratories had at that stage sought to renew their contracts to review tests for the HSE, which were due to run out on July 31, 2016.

It was noted in the same memo that if no agreement was reached, a tender process could take up to two years — severely delaying smear test services.

A document from a July 2016 meeting between the department and the HSE said officials were told 86 letters had “been issued to treating clinicians” and “a further 200 letters will issue during July-August 2016 where cytology was reviewed”.

The same document said officials should prepare for negative media coverage as “given the volume of letters that will issue over the coming weeks, it is possible that individual cases would appear in the public domain”.

The tranche of documents released last night also outlined a series of other previously unknown issues in the scandal, including that:

- Senior Department of Health officials including Dr Holohan knew far more about the situation two years ago than previously claimed, due to a series of meetings between March and September 2016;

- 128 women developed cervical cancer within three years of being told there was no sign of the condition in their smear tests;

- Doctors with concerns over the HSE’s communications plan for the scandal should contact a PO box in Limerick instead of tell their patients themselves.

While the documents prove the department was aware of the scandal in 2016, Taoiseach Leo Varadkar said last night they do not show he was aware of what was happening — a claim Fianna Fáil TD Marc MacSharry last night responded to by saying to the Taoiseach and health Minister Simon Harris: “I simply don’t believe you”.

Meanwhile, Mr Harris said last night it is “abundantly clear” the scandal has “raised very great issues of trust” in the HSE and that he will push for the speedy introduction of mandatory open disclosure.