The entry for M Roberts, head girl in 1943, takes up a good chunk of the oak noticeboard recording the honours harvested by generations of old girls, their minds expanded and their backbones stiffened by an education at Kesteven and Grantham Girls’ School.

The noticeboard, along with the almost unaltered Edwardian school holding it, has just been listed at Grade II by the government, partly in honour of its most famous pupil; Margaret Hilda Roberts, later prime minister Thatcher, later still Baroness Thatcher of Kesteven.

Culture Minister Ed Vaizey said: “This is an outstanding example of an Edwardian grammar school with an eclectic architectural character and built by the architect HH Dunn, who specialised in education buildings. But, as well as its architectural interest, the school has huge historical interest, and the education Margaret Thatcher received there was a formative experience which went on to affect her life and political convictions.”

The listing is on the advice of English Heritage, where Emily Gee, head of designation, said: “This handsome Edwardian grammar school possesses real historic interest for its association with Great Britain’s first female prime minister.

“Margaret Thatcher’s connection to her home town was a poignant one, and her views on education were no doubt shaped by her experiences in this building, where her maiden name is recorded on the head girl board.”

The listing adds to a growing Thatcher tourist trail in the town. Five months after her death fundraising continues for a statue of her, while a plaque marks the corner shop where the grocer and alderman’s daughter grew up and formed her political convictions of thrift, hard work and balanced books. Among the town museum’s proudest possessions are examples of her trademark blue suit and black handbag which she donated herself.

She first attended Huntingtower Road primary, and won a scholarship to Kesteven and Grantham Girls’ School, now an academy, then still run by its founder, Miss Gladys Williams. Her name went on the oaken head girls’ board in 1945, two years after she left the school for Oxford, but it needed repeated updating, eventually taking up twice as much space as most of her peers, recording that she became BA Hons Nat Sc Oxon; B Sc; Barrister-at-Law. And much, much else, for which there wasn’t room on the board.

The school is immensely proud of her. She returned in 1986 to unveil a Wedgewood plaque bearing her portrait in the hall. The school’s motto translates as “from this place take true inspiration” and she commented: “It certainly came true for me. From this place I did take inspiration.”

She returned again in 1986 to open the Roberts Hall, named not in her honour but for her father, the much cited alderman Alfred.

The culture department has added images of the school to its flickr site, with the perhaps significant note: “The photo owner has disabled commenting.”