The former BBC journalist at the centre of an official secrets row has accused the Ministry of Defence of endangering her life by leaking information to the press.
Yesterday the MoD confirmed that a soldier, named in the press as Lt Col Owen McNally, had been arrested in Afghanistan on suspicion of breaching the Official Secrets Act.
The paper reported that be had become "close" to former journalist Rachel Reid, who is the Afghanistan researcher for Human Rights Watch.
Writing in The Guardian today, she said: "Whatever the MoD has whispered into the ear of the Sun, Col McNally and I met only twice, both times in a purely professional capacity, both times at the Nato military HQ in Kabul.
"Both times we met to talk about civilian casualties from US and Nato air strikes.
"What has happened in the last couple of days has been bewildering. I do not understand how these two meetings might have led the British government to accuse McNally of a serious crime that could lead to a hefty jail sentence, and why my government might want to see my reputation dragged through the mud, when I live in a country where a woman's reputation can mean her life."
She added: "If the ministry had been seriously concerned that one of their officers was leaking information, why leak it to the media?
"Why was my name released to the media by the MoD, with a - nudge, nudge, wink, wink - libel that our relationship was 'close'?
"They would know exactly what impression they were creating, and presumably decided that my reputation was expendable in order to ensure coverage of their 'story'."
"Why have journalists not been asking questions about why the MoD has been encouraging them to publish a vicious, false slur about me in order stop me from doing my job for Human Rights Watch in asking for information from the Nato official in charge of monitoring civilian casualties?"
According to some estimates – up to 1,000 civilians a year have been killed in the crossfire since the US-led invasion of Afghanistan began in 2001.
Reid's lawyer, Mark Stephens of Finers Stephens Innocent, said: "Ms Reid acted throughout with propriety and professionalism. Any suggestion or imputation made to the contrary - that she had a relationship with the colonel that was other than at arm's length - will be met with legal proceedings.
"Ms Reid is an experienced former BBC journalist and it appears very likely that someone at the MoD is engaging in black propaganda, dishonestly spinning that there was a 'close relationship' - nudge, nudge, wink, wink.
"This behaviour by an agent of the British government is truly shocking, and the person concerned must be unmasked and punished."