23/07/2015 10:14 BST | Updated 23/07/2016 06:59 BST

Labour Needs a Leader Who Actually Wants to Be Prime Minister, And Who the Electorate Thinks Can Be Prime Minister

I'm beginning to get really angry. I represent one of the most deprived seats in the country. It's had a Labour or Lib/Lab MP ever since miners were given the vote. We have enormous social challenges to address. A third of all children grow up in poverty. But for all the good work of the Welsh Government improving mental health provision, getting young people into work and protecting local authority budgets, I am utterly impotent in opposition. I can't abolish the bedroom tax. I can't prevent another round of 40% cuts to Welsh budgets. And all I can do when the Tories cut inheritance tax for the richest 5% rather than boost support for disabled people trying to get into work, is rant and rail and rave.

So I want to say to anyone in the Labour Party who really thinks that it's more important to burnish our socialist credentials than to sully our hands by actively pursuing power, please think again. Of course we have to hold firm to our principles - equality, social justice, international solidarity, fair rewards for fair endeavour - but we have to be absolutely disciplined in our pursuit of policies that can command the support of the whole country. Anything else is just a luxury that my constituents can ill afford.

It may be uncomfortable for us, but we will have to reach out to people who voted Ukip, Tory and SNP this May. Last year I spent the best part of eighteen weeks on three by-election campaigns in Newark, Clacton and Rochester and Strood. None of them was very propitious territory for Labour - and we came third in each case, despite having really impressive candidates. It's true that these were really battles between Ukip and the Tories and the Tories threw not just the kitchen sink but the butler's sink, the oven and the butler himself at the contests, so Labour got squeezed out just as the Lib Dems started their extraordinary vanishing trick.

But large chunks of each of these seats have been represented in the last twenty years by a Labour MP and the truth is that as nice as it is to pile up vast majorities in our heartlands we will have to make headland advances in seats like these if we are to stand a chance of winning a General Election. That's the magnitude of the task ahead of us.

Which takes me to the question of leadership. We will only advance as a party if we have a leader who actually wants to be Prime Minister and who the electorate (in Clacton as well as Rhondda) thinks can be Prime Minister. That will require the ability to be decisive, to make your mind up and stand your ground. It will have to be someone who can unite the party and take the fight to the Tories.

To my mind, the last few days have shown that Yvette Cooper is the only candidate with the personal resilience necessary. I saw it when Andrew Neil was trying to bully her on the economy. Never shouty, never sharp, she saw him off with calm self-assurance. On the LBC hustings, too, she was witty and warm. And on the Today programme this morning up against John Humphrys she showed that she doesn't get flustered by assertive interviewing, that she knows how to take on the Tories with wit and intelligence, and that she will be a credible alternative Prime Minister from the moment she steps into the role.

Above all she proved that a lot of the debate about the leadership election is presenting members and supporters with a false choice between voting with your head and voting with your heart. The truth is that if we get this leadership election wrong, the nation may well vote with its feet, consigning Labour to the margins of political history. What Yvette is offering is a clear vision for the future shot through with optimism, rooted in Labour values and principles and rich in policy detail (such as her commitment to end child poverty, her policy of investing in the hi-tech jobs of the future and her summer-long campaign against the dogmatic Tory "two child policy"). Above all she knows that if Labour is to stand a chance of victory we will have to do some very tough thinking so that we can inspire people with a vision of a different future.

In the end the whole point of Labour is to put our principles into practice for the sake of the thousands of vulnerable people who have faced five years of hardship thanks to Tory cuts and are now facing another five years of even worse. We simply cannot afford to waste any time in taking the fight to David Cameron. While our focus is rightly trained on how we achieve a Labour government in five years' time, we need someone who can hit the ground running from the very first day of leadership. Yvette has proven she is a woman who is ready to lead - it's up to all of us to make sure she has the chance.