Education is like a "master switch" that opens up opportunities, Bill Gates has said, as it was announced that a Briton is among 10 teachers in the running for a million-dollar teaching prize.
Andria Zafirakou, a teacher at Alperton Community School in Brent, north-west London, has made it onto the shortlist for the fourth annual Varkey Foundation Global Teacher Prize, which recognises an individual who has made an outstanding contribution to the profession.
In a video message, Mr Gates paid tribute to the finalists, saying research has shown that a great teacher can be "the most important factor" in whether students get a great education.
The Microsoft co-founder and billionaire philanthropist said: "When you think about what drives progress and improvement in the world, education is like a master switch - one that opens up all sorts of opportunities for individuals and societies.
"And research has shown that having a great teacher can be the most important factor that determines whether students get a great education."
The finalists were chosen partly for their proven abilities in inspiring students and helping them to learn, Mr Gates said.
"Just as important, these teachers are leaders who have innovated in the classroom and mentored their colleagues," he added.
"They have demonstrated the kind of collaboration - teachers and schools working together - that can give all students the opportunity to get a great education."
Ms Zafirakou said she decided to submit an application after reading about it.
"When you read about why they are doing this - sharing good practice, raising the profile of teachers and how fundamental they are in society - that was why I wanted to apply," she told the Press Association.
The pupils at Ms Zafirakou's inner-city school, which is in one of the poorest areas of the country, come from a variety of backgrounds.
She has learnt how to say basic greetings in many of the 35 languages spoken at the school, including Gujarati, Hindi, Tamil and Portuguese, to help parents feel welcome and included.
"If you have somebody who can connect with you and appreciate your background, then that's special," she said.
She added that greeting someone in their language "helps to break down barriers and enables families to engage more in the school community".
Ms Zafirakou has helped to set up clubs and societies for students, redesigned the curriculum with her fellow teachers to make it relevant to pupils' lives, and is known for taking time to understand her students' lives, such as visiting their homes, taking the bus with them and welcoming them at the school gates.
She said: "By getting pupils to open up about their home lives, I discovered that many of my students come from crowded homes where multiple families share a single property.
"In fact it's often so crowded and noisy I've had students tell me they have to do their homework in the bathroom, just to grab a few moments alone so they can concentrate.
"I also found that some were being forced to play truant to cook meals in the allocated time slot they were permitted to use their shared home kitchen.
"Others could not participate in extracurricular activities after school because they had to take on parental responsibilities like collecting their brothers and sisters from other schools.
"Discovering all this prompted me to organise additional provision within the school day and often at weekends to help students have the opportunity to progress.
"This included giving them access to a quiet place to do their art work, as well as time to participate in extracurricular activities."
The other finalists, drawn from 30,000 entries from 173 countries, are from Turkey, South Africa, Colombia, Philippines, United States, Brazil, Belgium, Australia and Norway.
The award will be presented at a ceremony in Dubai on Sunday March 18.