A teacher from north London, named as a top-10 finalist in a global teaching award, has warned of the poor living conditions of her pupils.
Andria Zafirakou says some pupils at her Brent secondary school have to do their homework in the bathroom, because their housing is so overcrowded.
The nominations were announced by technology billionaire Bill Gates.
Education is the "master switch" for progress in society and individual lives, said Mr Gates.
The Microsoft co-founder and philanthropist revealed the top 10 teachers in the Global Teacher Prize organised by the Varkey Foundation, with the winner to receive $1m (£720,000).
'Playing truant to cook'
These included Mrs Zafirakou, an art and textiles teacher from Alperton Community School in north London.
She has been nominated for her work with deprived pupils, working with their families at home as well as in the classroom.
"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," said Mrs Zafirakou.
"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 extra-curricular activities after school because they had to take on parental responsibilities like collecting their brothers and sisters from other schools," said Mrs Zafirakou.
Raising status of teaching
In response, she organised extra lessons during the day and the weekend, including giving pupils a quiet place to work.
She had learned basic phrases in the 35 languages spoken by pupils at the school and helped teachers work with other services, such as local police and mental health specialists.
The nominations for Andria said:
"I am submitting a nomination for a teacher who is a true gem, one who inspires such possibility and potential in her students, their parents, the staff, her peers, the local community, and future teachers and leaders."
"A phenomenal teacher and leader. She is guided by a moral compass that underpins a passionate desire to give every student at her school the world - no ceilings, no limitations, no boundaries."
"She is a force to be reckoned with when it comes to ensuring that students deserve the best education possible."
"One lady with care and passion can make a huge difference to the lives of many. She is upbeat, full of character, highly regarded and I wish all schools were blessed with a senior leader such as her!"
The finalists have been drawn from more than 30,000 nominations in 173 countries, with the top 10 coming from schools in countries including Brazil, Australia, Colombia and South Africa, as well as the UK's representative.
The competition is intended to raise the status of the teaching profession and Bill Gates pointed to the importance of their work.
"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," said Mr Gates.
Sunny Varkey, whose foundation set up the annual international teacher prize, said he wanted the finalists' stories to "inspire those looking to enter the teaching profession" and to "shine a powerful spotlight on the incredible work teachers do".
The other nine finalists for the Global Teacher Prize 2018 are:
- Nurten Akkuş a pre-school teacher and principal, Samsun, Turkey
- Marjorie Brown, history teacher, Johannesburg, South Africa
- Luis Gutierrez, social science teacher, Bogota, Colombia
- Jesus Insilada, English teacher, Iloilo, Philippines
- Glenn Lee, engineering and technology teacher, Hawaii, United States
- Diego Mahfouz Faria Lima, school director, Sao Paulo, Brazil
- Koen Timmers, lecturer and computer science teacher, Heusden-Zolder, Belgium
- Eddie Woo, maths teacher, Sydney, Australia
- Barbara Anna Zielonka, English teacher, Nannestad, Norway.