Nick Clegg has backed the decision to send top civil servant Sir Jeremy Heywood to the Guardian and urge them to destroy classified data because it was "preferable" to taking legal action.
David Cameron directed Sir Jeremy to contact the newspaper about classified material handed over by Edward Snowden.
The Deputy Prime Minister's spokesman said: "(Clegg) thought it was reasonable for the Cabinet Secretary to request that the Guardian destroyed data that would represent a serious threat to national security if it was to fall into the wrong hands.
"The Deputy Prime Minister felt this was a preferable approach to taking legal action. He was keen to protect the Guardian's freedom to publish, whilst taking the necessary steps to safeguard security.
"It was agreed to on the understanding that the purpose of the destruction of the material would not impinge on the Guardian's ability to publish articles about the issue, but would help as a precautionary measure to protect lives and security."