By Alastair McIndoe, Philippines Correspondent

MANILA, PHILIPPINES - For over a decade, former school supervisor Antonio Calipjo Go waged a lonely crusade, painstakingly exposing grammatical and factual errors in textbooks used in Philippine state schools.

He threw in the towel last year.

'I just felt that there had been no improvement,' he said. The 58-year-old educator quit the profession to run his family's farm in southern Philippines.

A new series of English textbooks being used by over 14 million pupils in public elementary schools has fired up his advocacy again. He claims that it is riddled with errors; over 500 of them alone in a 208-page textbook for sixth graders.

'I couldn't bear to see these errors; I had to come back,' said Mr Go.

He has circulated a paper, Burn After Reading, that lists mangled sentences like:

'Is what this man say true?' asked the judge.

'He hid for hours the whole day.'

Education Secretary Jesli Lapus said the series, English For You And Me, has been re-evaluated and corrections will be put in a teachers' guide.

'Some (of Mr Go's) errors were confirmed, some not,' he said. The textbooks were written by a Filipino author and published by a local company. University academics were hired to check the copy.

Last year, Mr Lapus ordered two textbooks withdrawn from private schools after they were found to contain 'major errors' that had been pointed out by Mr Go.

Errors highlighted by him in a Tagalog-language series of social-studies textbooks in 2004 resulted in a lengthy teacher's guide correcting the mistakes.

Mr Go blamed the lax evaluation of manuscripts on the government agency tasked with reviewing them. He also criticised 'publishers with only profit on their minds'.

Some reading his list of errors in the English textbooks may not agree with all his calls. But his dogged campaign to improve the quality of textbooks has won him sympathetic coverage in the media.

It also reflects concerns over the slipping standard of English in the Philippines, although the country still has a considerable advantage over many of its neighbours.

With nearly 20 million children in public education in the Philippines, textbooks are a huge business here. They are replaced every five years for core subjects.

The Department of Education (DepEd) said textbook procurement, which was notoriously prone to corruption, has improved markedly and the system is now recognised by the World Bank. The new series of English textbooks was funded by a soft loan from the multilateral bank.

According to the DepEd, textbook costs have fallen by three quarters from a decade ago. Even so, calls to improve quality control are intensifying. 'The DepEd must... put in place an effective system of checking the accuracy of textbooks,' said The Philippine Star in a recent editorial.

This article was first published in The Straits Times.