07/08/2015 12:50 BST | Updated 07/08/2016 06:59 BST

Labour's Next Leader Will Undoubtedly Play a Key Role in the Fortunes of the LGBT Movement

Over the past few months, numerous cities across the UK have played host to pride marches and events. These parades, with an ever growing list of marchers, ranging from the LGBT police to gay choirs have now become major fixtures in city calendars. However, it wasn't too long ago that we lived in a society where section 28 was in place in our schools and openly LGBT servicemen and women couldn't serve in our military. Today, the LGBT legislative jigsaw is almost complete and our Parliament has the highest number of sitting openly gay politicians in the world. I'm proud of the role that the Labour Party has played in guiding the country down this progressive road and I'm particularly proud of the role Yvette Cooper played in helping the movement reach the most recent milestone in the struggle for equality -same sex marriage.

We all remember Yvette's humorous and moving speech in the commons debate on same sex marriage (she was rightly awarded politician of the year by PinkNews) - that's leadership.

At the start of the 2010 parliament, it was Yvette, then Shadow Home Secretary and Shadow Minister for Women and Equalities, who put pressure on the Tories when they wavered in light of vocal opposition from the grassroots of their party - that's leadership. During the passage of same sex marriage, Yvette demonstrated her ability to build broad-coalitions, leading roundtables featuring representatives of various faiths who collectively backed the idea that two people should be able to get married irrespective of their sexuality. On the back of this, she campaigned successfully to ensure those religious groups that wanted to were able to celebrate same sex marriage. An important intervention, given that the debate was often portrayed fight between liberals on one side and religion on the other.

Why is all of this important in the context of the leadership election? At the heart of what we care about and fight for in Labour is a belief in equality - political as well as economic. Labour has always marched side by side with those who have faced discrimination - from the women who were denied the vote until the beginning of the last century, to the black communities who have been blighted by racial prejudice since the Windrush landed on our shores. Labour's involvement in the struggle for gay equality is now part of that rich history. And that history now creates a strong imperative for our party to elect a leader who has a proven record of leading the fight for LGBT rights. Not following a trend because it seems the popular thing to do, but embracing the cause because it's the right thing to do. We need such a leader because there is still more to do.

Yes, we now have corporates falling over each other to sponsor pride events, but there are still gay couples in cities across the UK who still fear holding their partner's hand in public because they fret about provoking violence. That's why, at the last election, Yvette called for tougher laws, making homophobic hate crime an aggravated offence.

Homophobic and transphobic bullying is sadly still a feature of many schools and workplaces. This is an issue that should be tackled head-on and that's why Yvette has campaigned consistently and passionately for compulsory sex and relationships education in schools.

Overseas, the situation is dire. Over 76 countries criminalise homosexuality, many of whom are members of the Commonwealth and are our allies. Surely now, like any good friend, the UK must have a serious, grown up conversation with countries where it's acceptable to hunt down gay couples, strip them and parade them naked through their community where they are subjected to insults, abuse and more.

We've come so far and yet there is some way to go. Labour's next leader will undoubtedly play a key role in the fortunes of the LGBT movement in this country and others. That is why as a party we have an obligation to scrutinise the records of those running for leader. I have, and that's why I'm backing Yvette.

Diana Johnson is a shadow home office minister and Labour MP for Kingston-upon-Hull North