The computer did not like 'repetition' in the speech
Winston Churchill's iconic "fight them on the beaches" speech did not make the grade when it was marked by a computer system, exam experts have said.
And extracts from modern classics such as Lord of the Flies by William Golding and a novel by Ernest Hemingway also failed to impress the computer.
All were marked down by a US program designed to assess students' essays.
UK exam boards and the qualifications development agency are experimenting with similar procedures.
At the moment, in the UK, computers are used only to mark some GCSE multiple-choice exam papers, in which there are right and wrong answers.
But exam boards are working on systems which would allow pupils to sit their exams online and for them to be marked by computer.
The agency responsible for developing such things - QCDA - has also run trials.
David Wright, chief executive of the Chartered Institute of Educational Assessment (CIEA), said Churchill's Battle of Britain radio speech in 1940, known as "Their Finest Hour", was marked down for repetition and the wrong use of words.
The institute - which represents exam boards and other bodies involved with testing and assessment - had put the speech and works by various authors through a system currently used in America.
The speech begins: "What General Weygand has called the Battle of France is over: the Battle of Britain is about to begin.
"Upon this battle depends the survival of Christian civilisation. Upon it depends our own British life, and the long continuity of our institutions and our Empire.
"The whole fury and might of the enemy must very soon be turned on us."
But Mr Wright said the computer marking the speech had not liked the repetition of the words "upon" and "our" and stated that the word "might" had been used wrongly.
Mr Wright said: "Emotion is something it can't deal with, human beings are built on emotion."
Only multiple choice exam papers are currently marked online
As for William Golding, an extract from Lord of the Flies was criticised as having "inaccurate and erratic sentence structure".
Ernest Hemingway's The End of Something was also marked as not up to standard.
In this case, the writer was said to have "shown lack of care in style of writing and vocabulary".
The deputy head of the CIEA, Graham Herbert, said: "It is an issue we have found with computer marking: a computer does not understand emotion and purpose."
The subtleties of the English language were something a computer could miss, he said.
Mr Herbert said online assessment was good for marking multiple choice or short answers.
But he added: "When it is being used to assess complex English language, then it begins to show its limitations."
One of the exam boards which had been looking at the possible use of computers to mark essay questions was Edexcel, but it has no plans to bring this in.
A spokeswoman for the exam board said: "We are not planning to use this technology for any GQ (general qualification) exams.
"Edexcel trialled computerised automated marking of essay questions on dummy GCSE scripts in 2006. These were very small scale and we have decided not to pursue them at this time."