Secret plans for the war in Iraq were passed to British Army chiefs by US defence planners five months before the invasion was launched, a court martial heard yesterday.

The revelation strengthened suspicions that Tony Blair gave his agreement to President George Bush to go to war while the diplomatic efforts to force Saddam Hussein to comply with UN resolutions were continuing.

Alan Simpson, the leader of Labour Against the War, said the documents were “dynamite”, if genuine, and showed that Clare Short was right to assert in her book, serialised in The Independent, that Mr Blair had “knowingly misled” Parliament.

The plans were revealed during the court martial of L/Cpl Ian Blaymire, 23, from Leeds, who is charged with the manslaughter of a comrade while serving in Iraq. Sgt John Nightingale, 32, a reservist from Guiseley, West Yorkshire, died after being shot in the chest on 23 September last year.

The court, at Catterick Garrison, North Yorkshire, heard that contingency plans were drawn up by Lt Col Christopher Warren, staff officer at Land Command, Salisbury, Wiltshire, who was responsible for operational training.

Lt Col Warren said US planners had passed on dates for which the invasion was planned. The hearing was told Army chiefs wanted the training for the Army to start at the beginning of December 2002. However, due to “sensitivities” the training was delayed.

The court heard the training for the TA began two months late and for the regular Army one month late. Lt Col Warren was asked what the sensitivities were. He replied: “Because in December there was a world interest. If the UK had mobilised while all this was going on that would have shown an intent before the political process had been allowed to run its course.”

The hearing was adjourned.