Here is the full text of the letter from Tory former Defence Secretary Michael Portillo indicating his intention to leave the Commons at the next election.
Congratulations on your unopposed selection as the leader of the Conservative Party. I am very pleased at the result.
Thank you for so generously suggesting that I should return from the backbenches to join your shadow cabinet.
As I told you, I have for some time been considering my future and I have decided that it should lie outside the House of Commons.
I have informed the Kensington and Chelsea Conservative Association that I will not offer myself for selection as the candidate for the next general election.
In those circumstances, of course I am unable to accept your offer.
I enjoyed the times when we served together in government and I know that you will make a most effective leader.
You have my support and warmest good wishes.
And beneath is the text of the response from new Tory leader Michael Howard after Mr Portillo turned down the offer of a post in the Conservative shadow cabinet.
Thank you for your letter and your support over the last week.
Recent events have demonstrated the Conservative Party's determination to unite and to look to the future not the past.
I am extremely sad that you have decided not to stand again at the next election.
Over more than 20 years you have made an immense contribution both to the Conservative Party and to our country. We are all enormously grateful.
Your departure from the House of Commons will be a great loss.
I wish you all the best for the future.
Rt Hon Michael Howard QC MP