The Cabinet Office says it won't release documents sent from the UK's Ministry of Justice over the Island's Assisted Dying Bill.
A Freedom of Information request asked for all correspondence with the UK about the law, which has yet to be given Royal Assent after almost a year.
But in its response, the Cabinet Office said releasing the material would affect trust and confidence between the Isle of Man and UK Governments.
And it added the UK had already refused a similar request under its own FOI legislation.
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