Baroness Warsi will face an investigation into whether she's broken ministerial rules and it's the first time the Prime Minister has decided that a minister needs to be investigated in this way.
Some are drawing a comparison between Jeremy Hunt, asking why she is being investigated and not Mr Hunt.
Downing Street says they are two very different situations.
But the issue for the Conservative Party co-chairman is she went on this official government trip to Pakistan in 2010 with a relative of her husband - who was also a business partner.
There is this potential conflict of interest, and that now needs to be investigated.
In a letter to Mr.Cameron she says:
On a personal note David, I am sincerely sorry for these difficulties.