Nick Timothy has resigned as Prime Minster Theresa May's co-chief of staff and written an article explaining his decision for the ConservativeHome website.
Here is his piece in full, as published on conservativehome.com:
Yesterday, I resigned as the Prime Minister's adviser.
Clearly, the General Election result was a huge disappointment. What lay behind the result will no doubt be the subject of detailed analysis for many months. My immediate reaction, however, is this.
The Conservatives won more than 13.6 million votes, which is an historically high number, and more than Tony Blair won in all three of his election victories.
The reason for the disappointing result was not the absence of support for Theresa May and the Conservatives but an unexpected surge in support for Labour.
One can speculate about the reasons for this, but the simple truth is that Britain is a divided country: many are tired of austerity, many remain frustrated or angry about Brexit, and many younger people feel they lack the opportunities enjoyed by their parents' generation.
Ironically, the Prime Minister is the one political leader who understands this division, and who has been working to address it since she became Prime Minister last July.
The Conservative election campaign, however, failed to get this and Theresa's positive plan for the future across.
It also failed to notice the surge in Labour support, because modern campaigning techniques require ever-narrower targeting of specific voters, and we were not talking to the people who decided to vote for Labour.
I take responsibility for my part in this election campaign, which was the oversight of our policy programme. In particular, I regret the decision not to include in the manifesto a ceiling as well as a floor in our proposal to help meet the increasing cost of social care.
But I would like to make clear that the bizarre media reports about my own role in the policy's inclusion are wrong: it had been the subject of many months of work within Whitehall, and it was not my personal pet project.
I chose not to rebut these reports as they were published, as to have done so would have been a distraction for the campaign.
But I take responsibility for the content of the whole manifesto, which I continue to believe is an honest and strong programme for government.
Turning to the future, nothing matters more than the good government of the country. The Brexit negotiations are due to begin, and if the United Kingdom is to get the right deal, there is no time to waste.
I hope the Conservative Party in Parliament gets behind the Prime Minister, and allows her the political space to negotiate that deal.
In the meantime, I want to place on record my sorrow for the Conservative Members of Parliament who lost their seats, several of whom are close friends.
I want to reaffirm my ongoing support for the Conservative Party and its principles. And I want to encourage all Conservatives to come through this difficult period, unite behind the Prime Minister, and focus on the need to heal the divisions in our country.
Fiona Hill also resigned as joint chief of staff.
Here is her statement on ConservativeHome:
"It's been a pleasure to serve in government, and a pleasure to work with such an excellent Prime Minister.
"I have no doubt at all that Theresa May will continue to serve and work hard as Prime Minister - and do it brilliantly."