She may be midway through fighting her husband’s American presidency campaign, but Michelle Obama still found the time to congratulate her favourite British school on their outstanding exam results last week.

Elizabeth Garrett Anderson (EGA) School in Donegal Street, Islington, which had a visit from the First Lady back in 2009, received a letter from the White House heaping praise on the students who achieved the school’s best-ever GCSE results this year.

She said: “I was thrilled to learn that this year’s grades were the school’s best ever, which is a testament to the dedication of the young women, the expertise of the staff, and the support of all of your families.

“This success proves what I have always believed – with hard work, commitment and determination, anything is possible.

“You have exciting lives ahead of you, and if you keep studying hard I know you will have the tools you need to achieve your dreams.”

Headteacher Jo Dibbs said: “We received the letter last week, she must have heard the news that we achieved our best-ever results which included some absolutely stunning achievements among our young women.

“What it shows is that she is still very much interested in the progress of the school.

“It was a very nice surprise. Even though she is a very busy woman at the moment, in the middle of a presidential campaign, she remembered EGA and the young woman here.”

Mrs Obama has a long history with EGA, dating back to her visit to the school in 2009 during which she delivered an inspirational speech about her own experience growing up in a working class Chicago neighbourhood – a moment later described in her biography as the point she “made sense” of her role as First Lady.

Mrs Obama went on to take 35 students from the all-girls school with her on a trip to Oxford University in 2011 and last year invited 12 students and Ms Dibbs to the White House in Washington.

The school saw an 11 per cent increase in the number of students obtaining at least five A* to C grades including English and maths this year – up to 56 per cent.

Many of the GCSE students who got to meet Mrs Obama said that her visit had given them an extra determination to achieve.