It's one thing to be criticised for poor English teaching, but another when you discover 21 basic English errors in the report from inspectors pointing out your faults.
So when Bob Bell, chair of governors at Broadmead nursery and infants in the London borough of Croydon, spotted the misspellings and rogue apostrophes in the Office for Standards in Education report, he saw red.
Inspectors, who visited the school in January, rated it as satisfactory.
But Tusha Chakraborti, the lead inspector, and her team judged English, and the teaching of writing in particular, to be unsatisfactory.
Mr Bell said: "I would question the ability to assess the teaching of English by an inspection team which itself is quite clearly incapable of writing acceptable English."
Guidelines from the education watchdog state that reports must be "well-crafted, clearly written, high-quality documents with accurate grammar and spelling".
Mr Bell, an IT project manager for British Telecom and school governor for the past 15 years, highlighted a catalogue of howlers in the report from inspectors.
He picked up factual mistakes, rogue apostrophes, plural verbs with singular nouns, misspellings and missing words and capital letters.
Examples include "Partnership with parents are satisfactory", "Both the schools' rate of authorised and unauthorised absence...", "Subject leaders have not received suffiecient trianing ot help them to do their job well" and "The school has made satisfactory improvement the last inspection in 1999" (the previous inspection was in 1998).
An Ofsted spokeswoman said: "The report was proof-read but unfortunately the corrected report was not then used as the master copy, resulting in an uncorrected version being sent to the school and Ofsted.
"The contractor has apologised to the chair of governors and a corrected version has been sent.
"Ofsted has removed the uncorrected copy from the website."
The apology to Broadmead follows another apology from David Bell, chief inspector, to Banham primary near Diss, Norwich, for an Ofsted report which wrongly said that it had serious weaknesses.
Headteachers might be forgiven for looking at the Ofsted guidelines to measure the standard of inspection report writing and asking themselves if satisfactory is good enough.