Walking through Harris Academy South Norwood, it appears like any other school, as it proudly showcases its pupils' achievements.

However, amongst children's artwork and awards, the halls are decorated with rainbow gay-pride flags.

That is because the secondary school is leading the way in promoting diversity and celebrating LGBT (lesbian, gay, bisesxual, transgender) rights.

And it is all down to one teacher, Daniel Gray - who took the brave decision to come out to 1,000 students.

He said: "I think it just takes one person to say 'It's OK' for the floodgates to open and for all these kids to just accept each other for who they are.

"Even if you don't know who you are, you maybe just feel a bit different, there's other people out there for you.

"You can be happy, you can be successful."

Mr Gray, 32, made the decision to be open about his sexuality in an assembly as part of LGBT History Month - having previously been told to keep his sexuality a secret while training to be a teacher.

"I was told categorically when I started to train to be a teacher nine years ago not to come out to my students," he said.

"They said you don't want to give them any more ammunition than they've already got, and that's really a very depressing and very sad way of looking at it.

"It's assuming the students are out to get you."

While training, Mr Gray said he was asked what he would say if a pupil were to ask him if he was gay.

"I said well I wouldn't lie and I would say I am, because I don't see a problem with it, and I've never seen a problem with it," he said.

Teaching at other schools, Mr Gray said he felt he had to avoid answering particular questions from students. But he was never comfortable following others' advice to keep quiet about such an important part of his life.

He said: "It's not like teachers are here to talk about their personal lives - they're not - but my not talking about my life, it's excluding those who feel like they can't fit in.

"It's always felt like I was withholding something. I'd never lie, but I'd change the subject. Luckily I haven't had too many of those questions, but I learn about students' lives, and it's just who I am to want to build positive relationships.

"You want to have a good relationship with your students, and part of that is being open about who you are."

So, as part of an assembly informing students what the school would be doing to mark LGBT History Month, a video was played in which Mr Gray bravely came out so he could increase the visibility of homosexual role models in the school.

Careful not to make his story the main focus of the assembly, Mr Gray said his admission was more of a passing comment to add context to the assembly's theme.

He said: "I went through all the things the school was doing for LGBT History Month, and then I just said, 'As a gay man, I know how important it is to have positive role models, and that's why we're doing this'.

"I was so relieved when it was done, and then the response was just like 'OK' and a few people shrugged. Most people weren't even bothered."

Mr Gray said this way of telling his students was intended to promote homosexuality as an ordinary thing which is a part of everyday society.

"It's not meant to be a big deal, it's not meant to be any different to how life always is," he said.

"I hate the world normalise, but by just talking about it in conversation, as opposed to announcing it, normalises it.

"Because it's not meant to be about me coming out, it's about what me coming out is doing for the school."

Coming out to the students, Mr Gray added, was part of showcasing Harris Academy as a place where students can feel safe and see diverse role models.

Reflecting on his own time at school, where Mr Gray was bullied for being different, he said he wanted to change gay pupils' experiences at school.

He said: "Every single day I was pushed in corridors, I was called names, I was insulted, I was sworn at, spat at and I had stones thrown at me.

"All because students suspected I was gay - I didn't even know I was at this point."

Mr Gray said that when he approached a teacher to report the bullying, he and a friend were told this was just something they would have to accept if they were openly gay.

"There was no one really visible to help me, so I had to help myself," he added.

As an openly gay teacher in his school now, Mr Gray wants to appear as a positive role model for students who may feel similarly.

"I want to make sure they feel safe like I never did," he said.

"If a student needs to speak about their sexuality, or just feeling a bit different, they might not choose to speak to me about it, but they know I'm there and I'm someone who's been through what they've been through."

Since coming out, Mr Gray said the response from staff and students has been "phenomenal".

The 32-year-old said teachers have rallied together and students have all been very supportive.

"What I'm seeing happening here now at this school is phenomenal," he said.

"Attitudes are changing, by being consistent and having a consistent message, we're talking openly about these things for the first time.

"We hear homophobic language at school and we stamp on it straight away, and we have done for years, but I think by personalising it, it gets people thinking differently, they know someone who is openly gay and could think 'oh, what would Mr Gray think?'"

Following the assembly, Mr Gray said he had a student who had never been taught by him tell him the assembly had changed his life.

"He was quite awkward about it, he didn't want a conversation about it, which I understand," he said.

"The fact that that opportunity was there for him, the fact that he doesn't feel like he's on his own any more I think is really, really powerful."

Other students have since approached Mr Gray for advice about coming to terms with their sexuality, and how they could come out to their friends and family.

He has even had emails from former students, who are gay, congratulating him and saying that they wish he had come out while they were at the school.

Comparing the way Harris Academy celebrates diversity to his school days, Mr Gray was visibly emotional, with tears forming.

He explained: "I actually feel a bit emotional [about it]. It's just so powerful. The impact we have on students' lives is immense as teachers.

"Knowing that this school can help shape those small number of students who really need it means the absolute world. It really, really does.

"Just to see those little stripy flags everywhere, it seems like a silly thing, but for those kids it's visible.

"Seeing something that's going to get young people the confidence they need - that's why we teach isn't it?"

As well as rainbow flags, the school is also incorporating books about LGBT figures into its library, and incorporating LGBT issues into lessons.

Beaming due to the school's work, Mr Gray said: "What would be amazing would be if this spreads. What if we started doing this in every school?"