Mr Morley was first elected to Parliament in 1987
This is my choice after discussing this with my family and my constituency party officers.
The last two weeks have been traumatic for me and I have to think of my family, and my health, both of which have suffered.
Nor do I want in any way to undermine the strong position the Labour Party has in this constituency in what will be a crucial election.
In saying this I want to stress I made a genuine mistake over my expenses. There are reasons for this and I am confident that my name will be cleared and I am ready to make my case to the Parliamentary Commissioner for Standards as soon as that can be arranged, and to co-operate fully.
I have never tried to duck responsibility for my mistake and I have repaid the amount in full. I do understand peoples' anger over the whole issue of MPs' expenses and their frustration.
For those who condemn me I would simply ask to be allowed the opportunity to present my case. For those who have supported me, particularly those who have urged me not to stand down, I'd like to thank them for their support and would ask them to give that backing to my successor.