A school with fees of £8,000 a term has been criticised for including a lunch of baked potatoes in an "austerity day".
St Paul's Girls' School in Hammersmith, west London, was accused by a former pupil of showing "utter contempt" with the exercise that resulted in money going to local charities.
The prestigious school, which usually serves the likes of seared cod, slow-cooked Moroccan lamb and duck leg confit, appeared to delete a post on Twitter about the "austerity" lunch.
The post, which was screen-grabbed and shared, said: "Today was the final Austerity Day of the year. Students and staff had baked potatoes, with beans and coleslaw, for lunch, with fruit for dessert.
"The money saved will be donated to the school's charities."
The post included pictures of the food described, as well as an image of what appears to be the arm of a butler or waiter lifting a lid from a platter containing just three peas.
Henna Shah, 24, a former bursary student at the school, said: "I am incredibly grateful to have gone to a school that has given me opportunities someone like me would never have had otherwise.
"Yet I recognise that few people like me get the chance to have an education like this on a bursary scheme like I did.
"I am highlighting this now because this is not about pulling the ladder up behind me - I joined the Labour party and work in politics now precisely because everyone deserves the best quality education.
"It is upsetting to see that on a day that is meant to be about compassion, the way it was presented showed utter contempt.
"Austerity is not about eating jacket potatoes once a term, it is about not being able to afford anything else."
A menu on the school website, for a week in May, gave a flavour of what is usually on offer for lunch at the school.
Pupils tucked into delights such as Malaysian snapper Curry with okra and tomato, warm chicken and asparagus Caesar Salad, and plum and blackcurrant sponge.
According to the school's website, the fee per term for the academic year 2017-2018 is £7,978, and for new entrants to the senior school (Year 12) the fee per term is £8,577.
The school fee includes lunch, the website said.
A food section on the website says: "Everyone knows teenage girls can be picky eaters, so we try to give them lots of choice.
"We regard the enjoyment of good and healthy food as a priority and lunch at St Paul's is a real highlight of the day."
In a statement, the school said: "For many years, along with many schools and places of worship in the country, St Paul's has arranged regular lunches when simple food is served and the money saved given to local charities.
"The aim is also to raise the awareness of our students to those less fortunate than themselves.
"We take our commitment to the wider community very seriously.
"The choice of the word 'austerity' is to draw attention to the fact that others around them are facing significant economic difficulties."
A Twitter account called @everydayhunger wrote: "Can they really be unaware that for families living in poverty today, this 'austerity' meal is completely out of reach?
"Maybe they should visit their local food bank to see what genuine poverty rations look like."
Twitter user Georgia O'Brien wrote: "One of the country's leading independent schools holding an 'Austerity Day' where students eat what is basically amounts to a standard state school dinner."