The Treasury wiped all data from more than 100 government-issued mobile phones last year because their users, including the department’s boss, entered the wrong pin.

In response to a freedom of information (FOI) request from the PA Media news agency, the Treasury said its IT desk had reset 117 of its 2,100 mobile phones in 2020.

With each reset, texts sent from those phones are likely to have been lost. This includes messages sent by Tom Scholar, the department’s permanent secretary, which MPs have said should be released. Scholar was asked earlier this year to disclose the communications he had with the former prime minister and lobbyist David Cameron.

Cameron had contacted old colleagues from his time in government to convince them to allow Greensill Capital, which has since collapsed, to be included in a Bank of England loan scheme. Questions were raised about what was said between Cameron and officials, and what – if anything – he had been promised. Scholar said he was unable to divulge the contents of his text to Cameron because they had been wiped from his phone when it was reset in June last year.

“Under government security as applies to mobile phones, if the password is incorrectly entered more than a few times, the phone is locked, and the only way to unlock it is to reset it,” he said.

“Resetting it means that the data on it is lost. I knew that when it happened last June, and I am certainly not the only person to whom that has happened.”

Users of government phones are required to change their pins and passwords frequently. The Treasury refused to say how often such changes are required, citing security concerns.

During a hearing of the Treasury select committee, one MP said there was a “public interest” in publishing Scholar’s text messages. Under FOI laws, the Treasury and other departments can be required to publish texts concerning government business.

The government has come under increasing pressure in recent weeks over transparency procedures. The Good Law Project said on Friday that it would be taking legal action over ministers’ use of private email addresses and WhatsApp accounts for government work.

“We don’t just think this situation is wrong – we believe it’s unlawful,” it said. “It flies in the face of government’s legal obligations to preserve official records, and undermines its ability to comply with freedom of information requests and the duty of candour required by the courts.”