Culture Secretary Nicky Morgan has confirmed she will stand down from the Cabinet in the forthcoming reshuffle.
The former Loughborough MP quit the Commons in the December election but was given a seat in the Lords by Boris Johnson – and retained her ministerial role.
Baroness Morgan of Cotes told the BBC's Political Thinking podcast: "I made the decision to leave the House of Commons and to leave ministerial life in December.
"I achieved one of those goals, I haven't quite achieved the other one but I do intend, when the reshuffle comes, that – although I love being Digital, Culture, Media and Sports Secretary – it is time for various reasons to take a step back from ministerial life."
She said she took the decision because of a "culmination of things", but that there was "one particular incident" when she was recommended to sit near the front of the train when travelling back to her constituency by a guard amid heightened tensions in Westminster over Brexit.
"I just thought, actually, is this really where I want to be in terms of the way I'm living my life, and so for me that crystallised it."
Lady Morgan was also asked about whether the UK still needs a national broadcaster.
She said: "I'm not sure people say we don't need a national broadcaster, but I think the question is – and it does come up on the doorsteps more and more – 'Why do I pay my licence fee? I don't watch it. I don't agree with it'.
"However, having said that, I think public service broadcasting, not just about the BBC, it's about our other main channels as well, is a very important debate.
"And I think we do need a national broadcaster with a very strong international footprint but also brand that people will turn to."