Sir Michael Fallon has resigned from his post as defence secretary.
Fallon stepped down saying his conduct had ‘fallen short’ of the required standards after allegations of inappropriate sexual behaviour.
BBC political editor Laura Kuenssberg said a ‘radical reshuffle’ was not expected, but instead a ‘sideways move or single shuffle up’.
Fallon is the first politician to quit following recently revealed claims of serious sexual abuse in Parliament.
He told the BBC that what had been acceptable 15, 10 years ago is ‘clearly not acceptable now’.
In his resignation letter, Fallon said a number of allegations that had surfaced about MPs, including himself, had been false, but said: “I accept that in the past I have fallen below the high standards that we require of the Armed Forces that I have the honour to represent."
He later told the BBC it was ‘right’ for him to resign, adding: “Parliament now has to look at itself and the prime minister has made very clear that conduct needs to be improved and we need to protect the staff of Westminster against any particular allegations of harassment."
Scottish Tory leader Ruth Davidson said the ‘tone of politics had changed’, and it was time to ‘clean out the stables’ in British politics.
She added: “It isn't actually about sex. It's about power. It's always about power. And we as elected representatives have to hold ourselves to a higher standard.
"We're in positions of power so we can make things better for who comes after, not so that we can exert that power in a nefarious way."