You used to be able to tell what sort of school someone went to merely by they way they reacted to that scene in Monty Python's Life of Brian in which a Jew is caught by a centurion writing subversive graffiti.

The centurion - played by John Cleese - does something worse than throwing him to the lions: he sets about correcting his Latin, in the manner of a sadistic schoolmaster.

Those in the audience who fall about laughing - because they remember qui vir odiosus (1) Latin lessons could be - are the ones who went to private schools. The kids from the state schools do not get really get the joke.

But that is beginning to a change. A study by the Cambridge Classic Project has discovered that there are now 459 state secondary schools teaching Latin. That is not very many, out of a total of 4,000, but in 2003 when Latin was available in only 200 state schools.

It is a rare bit of good news for those who worry about the chronic decline of classical education. There was a protest yesterday outside the House of Commons by sixth-form girls from Godolphin and Latymer school, in Hammersmith. Dressed in ancient costumes, they were complaining about the abolition of the last remaining ancient history A-level. A petition posted on the Downing Street website has attracted more than 4,000 signatures to the cause.

But those who hold that Latin is condicio sine qua non (2) of a rounded education can take heart that it is now being taught in racially mixed inner city comprehensives in places such as Tower Hamlets and Kilburn.

Another sign that Latin is not quite dead is the extraordinary success of a book by the former Daily Telegraph journalist, Harry Mount, called Amo, Amas, Amat and all that - How to Become a Latin Lover which sold 70,000 copies in the UK. Mr Mount has now been paid a £125,000 advance for a new edition being produced, mutatis mutandis (3), for the US market.

Objectors might say ars long - vita brevis (4), and that children in inner city comprehensives have more important things to do than pore ad nauseam (5) over their Latin vocabularies, struggling to decline nouns and conjugate verbs.

But Lorna Richardson, who runs the Iris Project, which campaigns for the study of classics in state schools, sees it as a valuable tool for improving literacy. "It really does make a difference - the children themselves say that," she claimed. "There are about 30 languages spoken in that one school. Many of the children have English only as a second language. They all say Latin helps with their languages, it helps with their English."

As part of a pilot project, the Iris Project added Latin to the curriculum in one Hackney school. This will be expanded in September to cover 12 schools. The course is funded by Cambridge University and other benefactors. They also produce a magazine aimed at making the classics fun, which is free for state schools and paid for by sales to private schools.

Boris Johnson, the Tory spokesman on higher education, said: "Latin is wonderful, and beautiful. Kids want something that is intellectually stimulating. It's the root of all romance languages. It's a fabulous mental discipline, yet it's unavailable for all but a tiny minority, and that's socially unjust."

Mr Mount is also adamant that learning to write in Latin is not simply ars gratia artis (6). He says there is a real quid pro quo (7) in having a Latin qualification on your curriculum vitae (8), because after all that time spent learning to distinguish a nominative from a genitive, "you'll never get an apostrophe in the wrong place again".

He added: "If children learn ethnic studies, in ten years they will earn absolutely nothing from it. The ones who learn Latin will be the ones who will be able to go on to jobs in the City, or as lawyers, or journalists.

"I think it's deeply patronising for people to suggest that pupils in ethnically mixed state schools should not learn the subject that is going to get them into the best paid jobs."

And that headline? It translates as: "What goes around comes around."

1 What a bore 2 Necessary condition 3 With the necessary changes 4 The work is hard and life is short 5 To the point of nausea 6 Art for art's sake 7 Something in return 8 The course of life

A Latin glossary

Annus horribilis: "Horrible year". The Queen's description of 1992, when the marriages of her sons Charles and Andrew broke down, and Windsor Castle caught fire.

Bona fide: "In good faith". To check if someone is bona fide is to see whether they can be trusted.

Carpe diem: "Seize the day". Enjoy the opportunity while it is there, as you may not get another.

Cogito ergo sum: "I think, therefore I am". The French philosopher René Descartes spent a long time trying to work out how he knew he existed. This was his answer.

Et tu, Brute: "And you, Brutus". Supposedly the last, reproachful words spoken by Julius Caesar as he was stabbed to death by his supposed ally. Say it to someone you thought was a friend who has ganged up against you.

Et cetera: "And the rest". Written as etc. Usually pronounced with a soft "c", though some say it should be said like "et caterer".

Ex officio: "From the office". Applied to committee members in place because of a position they hold. Tony Blair and John Prescott are ex-officio members of Labour's National Executive - but not for much longer.

Exempli gratia: Usually written as eg, meaning "for example"

Hocus pocus: A corruption of hoc est pocus ("this is the cup" ) used in the Catholic Mass, which now signifies bewildering nonsense.

In flagrante delicto: "While the crime is blazing". Caught in the act.

In vino veritas: "In wine - the truth". Drink much alcohol and you may blurt out that which you should have kept to yourself.

Ipsos custodes: Short for quis custodiet ipsos custodes ("who will guard those who guard?"), one of democracy's oldest conundrums.

Non compos mentis: "Not in control of the mind". A legal term meaning insane, and not criminally responsible. Also used to describe someone with a hangover.

Nota bene: "Note well". Usually seen as n.b.

Quod erat demonstrandum: "That which was to be demonstrated" . Mathematicians write Q.E.D. at the bottom of a completed proof.

Post mortem: "After death". A pathologist's examination of a corpse, an expression also used colloquially to describe any investigation held after the event.

Status quo: "The state in which". Long before it referred to a rock band, the term was an abbreviation of status quo ante bellum (" the state of things before the war"), a basis for negotiating a truce and troop withdrawal.

Sub judice: "Under a judge". Once someone has been charged with an offence, ie. their case is officially under consideration, there are strict limits to what may be said about the case.

Sub poena: "Under penalty". If a court has ordered you to appear to give evidence, and is going to punish you if you refuse, you have been "subpoenaed".

Vice versa: "With position turned". Implying that a sentence would still be true if the subject and object were interchanged.