Three trust chief executives have openly attacked the prime minister’s chief adviser Dominic Cummings for allegedly flouting the lockdown rules.

Kathryn Thomson, chief executive of Liverpool Women’s Foundation Trust, today criticised Mr Cummings on the Twitter social media site.

She wrote: “NHS staff and other key workers going above and beyond to protect our society. In our hospital we have had to make difficult decisions about dads not attending scan appointments. Limiting parental access to the Neonatal Unit and #cummings flouts the rules. Disgraceful!!”

On Saturday, Bradford Teaching Hospitals FT chief executive Mel Pickup also posted on Twitter.

Under a picture of the prime minister defending Mr Cummings during the government daily briefing, Ms Pickup wrote: “To deter me ever from getting too big for my boots my mum always taught me that no-one is indispensable. Turns out some are”

East Sussex Healthcare Trust chief executive Dr Adrian Bull posted: “In crisis, to avoid confusion & ensure decisive action, it is right to support & follow leaders accepting they will make mistakes along the way. But they must lead by example as well as dictat.The Cummings case seriously undermines the leadership of this crisis. He should resign.”

The comments were all made before the press conference given by Mr Cummings on Sunday afternoon.

The three chief executives also received support from other trusts’ executive and non-executive directors, and other senior figures voiced their concerns.

Bolton FT chair Professor Donna Hall, replied to Ms Pickup, saying “So right Mel unbelievable hubris”, Surrey and Sussex Healthcare Trust chief information officer Ian McKenzie, replied “well said”.

Tameside and Glossop Integrated Care Trust executive director of estates and facilities, Paul Featherstone replying to Ms Thomson wrote: “Agreed. Disgraceful behaviour from #cummings who should resign if the Prime Minister hasn’t got the courage to do the right thing.”

Rachel Hurst, deputy director of finance at Bridgewater Community Healthcare FT, tweeted: “Enough is enough.”

Open criticism of senior government figures by serving NHS executives is very rare. Former NHS Confederation chief executive and NHS Providers chair Dame Gill Morgan tweeted: “I don’t remember ever seeing this” in response to the criticisms.

On Saturday, health and social care secretary Matt Hancock wrote: “I know how ill coronavirus makes you. It was entirely right for Dom Cummings to find childcare for his toddler, when both he and his wife were getting ill.”

The Faculty of Public Health became the first official NHS body to join the criticism of Mr Cummings, tweeting: “We are deeply concerned that recent actions from government appear to undermine essential public health messaging at this crucial time. It is vital that all in society continue to follow guidance to prevent the spread of covid-19 and save lives. If there is doubt regarding the actions of those involved with government, FPH supports at the very least, an inquiry into the matter.

NHS Confederation chief executive Niall Dickson said: “It is not for us to comment on the merit of individual cases nor to comment on the actions of any member of the Prime Minister’s team. However, whether or not any criticism is justified, we and our members are concerned at the damage that may be done to public and NHS staff confidence in government guidance because of the way this story has unfolded. We cannot stress too much that the guidance has saved tens of thousands of lives and that following the guidance in the weeks ahead is going to be as vital as ever, when discretion will inevitably be greater as the lockdown eases.”