Cheating in exams is fairly common in the Indian state of Bihar, but new images have emerged which show just how large-scale and blatant the practice is.

Many students smuggled in textbooks and notes into the examination centres despite tight security - and parents and friends were photographed scaling the walls of test centres to pass on answers to students during the current secondary school examinations.

The examinations, held by the Bihar School Examination Board (BSEB), began on Tuesday and are scheduled to go on until 24 March. Officials say more than 1.4 million students are taking the tests.

Most of the incidents of cheating this year have been reported from Saharsa, Chhapra, Vaishali and Hajipur districts.

Local newspapers have been full of photos of parents and relatives trying to help their children cheat even at considerable risk to their own lives, BBC Hindi's Manish Saandilya reports from the state capital, Patna.

Some photos even show policemen posted outside the centres accepting bribes to look the other way, our correspondent adds.

Photojournalist Dipankar, who took the photos in Saharsa district, says when he went into the examination hall and began taking pictures, the students did not seem worried at all.

Despite the many reports that have appeared in the local newspapers, the authorities seem uninterested in taking any action against the students, he says.

Dipankar says during a raid at just one school on Wednesday, the authorities seized sheets containing answers which filled up nine sacks.

Nearly 20 parents were detained briefly for trying to help their children cheat, but they were let go after a warning, he adds.

At some schools, like this one in Saran in Chhapra district, parents also clashed with the police.

Those caught cheating can be barred from taking an examination for up to three years, they can also be jailed or ordered to pay a fine, but punishment in such cases has rarely been reported in Bihar.

Education officials say they are committed to holding free, fair and peaceful examinations, and that examination centres are being filmed and special "flying squads" of officials are making surprise visits to the centres.

They say at least 400 students who have been caught cheating have been expelled.

But they say the government alone cannot stop cheating without help from students and parents.

"What can the government do to stop cheating if parents and relatives are not ready to cooperate? Should the government give orders to shoot them?" the Times of India quoted Bihar Education Minister PK Shahi as saying.