Vital services such as hospital cleaning should be run by public servants and ministers must take responsibility when things go wrong, the shadow attorney general has said.

Baroness Chakrabarti said it was “all very well” for Theresa May to say huge fines will be imposed on irresponsible company bosses who “line their own pockets”, and said there needed to be ministerial responsibility.

Lady Chakrabarti suggested that the state take responsibility for non-core services, such as hospital cleaning, because “cleanliness in a hospital is quite often matter of life and death”.

“It’s all very well for Mrs May to now say she’s going to sting these executives – there’s got to be a little bit of ministerial responsibility in all of this as well,” she told the BBC’s Sunday Politics.

“One of my concerns is that when vital public services of a kind that they’re almost constitutional, for example prisons, get contracted out what you’re actually devolving is ministerial responsibility.

“If something goes terribly wrong, whether in a vital utility or whether it’s a matter of security or infrastructure, and ministers of whatever colour just put their hands up and say its wicked executives, its the wicked company.

“What we need is ministerial responsibility, what we need is oversight.

“Of course we want a thriving private sector, but some vital services need to be run by public servants and with ministers held to account.”

She continued: “I believe in a mixed economy and I know that my colleagues do too, but there are times when some things need to be in public hands.

“That will include on constitutional grounds where you’re talking about people’s human rights and people’s basic security, that will also mean sometimes when you have a big organisation and outsourcing is used to grind down the working conditions of some workers and break down the sense of community and solidarity between them.”

Lady Chakrabarti said that while there were “some things” the private sector does better: “I think in some circumstances, I think maybe hospitals are a better example because of course cleanliness in a hospital is quite often matter of life and death.

“So I think sometimes it is better even for something that is not a core service like cleaning to be in public hands.”

Asked about Sunday Times reports that Momentum is trying to make it harder for MPs to be confirmed as candidates for the next general election, Lady Chakrabarti said: “My understanding is that Momentum is not prioritising the selection of some candidates over others – they are an invigorated movement, part of the Labour movement, which has always had various strands within it.”