Civil servants are bracing for harsh criticism of top Whitehall officials' behavior in the Sue Gray party gate report after the government's former ethics chief apologized for attending an illegal gathering.

While there is speculation about whether Boris Johnson will be fined for the lockdown parties at No. 10, there is also a concern in Whitehall about how to deal with the fallout from senior civil servants being implicated as gathering organizers when the full report is released.

See this: A timeline of scandals: Boris Johnson partying

This comes as Helen MacNamara, the former Cabinet Office head of propriety and ethics, issued an apology after a leak named her as one of 20 people fined following a Metropolitan police investigation.

There is concern that details in Gray's report, herself a senior civil servant, will cast some civil servants in a negative light, and that there may be evidence that some knowingly broke rules when organizing gatherings, potentially leading to disciplinary action, according to a senior source.

Gray has the authority to name senior civil servants in her report, but she may choose not to do so. In her interim report, she did not name anyone and only mentioned a "senior official whose primary function is direct support to the prime minister" – a reference to Martin Reynolds, the principal private secretary.

The government has agreed to reveal whether or not cabinet secretary Simon Case receives a fixed-penalty notice, but has said it will keep other names private. Gray will not know who has been fined when she publishes her report following the conclusion of Scotland Yard's investigations.

Downing Street defended the "anonymous process" of the Met investigation on Monday, in which the names of those fined are not officially released. However, some Conservative MPs are growing increasingly dissatisfied with the "drip-drip" of revelations, with backbencher Steve Brine saying, "I would have thought that the best thing is just transparency, open the curtains."

The Met is expected to issue a new wave of fines in the coming weeks, with Gray publishing her full report as soon as possible after that, possibly after the local elections purdah is over in May.