Microchips will be placed in packets of exam papers this summer as part of efforts to stop tests being leaked online, an exam board has said.

Pearson, the parent company of Edexcel, said the pilot scheme would allow it to track the date, time and location of exam packs in case they are opened early.

It comes as prosecutors said they were considering criminal charges after A-level maths papers from 2017 were leaked online ahead of the test, leading to replacement questions being issued at the last minute.

An investigation into a second A-level maths paper leak last year is continuing.

Vice-president Derek Richardson wrote to headteachers saying that “breaches of security can significantly undermine trust in the system” and it would continue to use tracking technology which helped in their investigations.

He added that both incidents were “caused by individuals deliberately setting out to subvert our controls” and urged headteachers to regularly inspect the area where papers are kept.

In a statement on its website, Pearson said: “In the UK summer examination series in 2017 and 2018, Pearson was subject to a limited external breach of its maths A-level paper. The police have made progress in their investigation from the first limited breach and have referred the first case to the Crown Prosecution Service.

“They are also finalising their investigation with the second case and we hope that they will soon be sending materials to the Crown Prosecution Service. We hope this latest update will act as a deterrent for any other isolated individuals that consider this course of action.”

Police told the company that evidence was given to the CPS in February.

Pearson said: “We have continued to support the police in their investigations, but due to the complexity and unusual nature of these cases, it has taken time to investigate. The police informed us that in February, they referred the first case to the Crown Prosecution Service with the aim of bringing charges against those arrested.

“The individuals responsible for these incidents are therefore now being held to account for the disruption that they caused. The police are finalising the second case and we hope that they will soon be sending materials to the Crown Prosecution Service.”

The 2018 leak saw a C4 maths paper apparently leaked online a day before thousands of candidates were due to sit the exam.

Students reported seeing the paper for sale online for £200, with the sellers sending over the first question to prove they had it, but demanding the cash before they would reveal the rest.