Defence chiefs have been accused by MPs of failing to properly protect British troops from "devastating" friendly-fire incidents.
An influential committee said a catalogue of delays to crucial new equipment meant "little progress" had been made towards meeting demands it made in 2002.
And it hit out at the failure to distribute thousands of aide memoire cards sent to Iraq among troops - saying they could have helped avoid casualties.
A young soldier whose armoured vehicle was fired on by a US aircraft was among six UK personnel killed in so-called "fratricides" by allied fire.
In a short but hard-hitting report, the public accounts committee said the Ministry of Defence had "failed to develop viable combat identification solutions to counter the risks of friendly fire incidents, despite their devastating effects."
While some improvements had been made, notably for air and sea operations, outstanding issues now had to be addressed "without further delay", the MPs ordered.
Their latest review found that more than half of projects to develop new kit to avoid the hazard had been deferred, delayed or "re-scoped" in the last four years. A crucial Battlefield Target Identification System was still several years away from being ready, restricting the value of other technology.
And with failure to reach agreement with allies leading to six years of delays, the MPs said a more limited home-grown version should be considered in the meantime to cover high-risk areas. The failure to give out any of the 60,000 combat identification cards was dubbed "particularly unfortunate" by the committee.
A Ministry of Defence spokesman said: "The MoD continues to place a high priority on improving combat identification for its forces through the right mix of organisation, equipment and training.
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"The focus is on increasing military effectiveness so that operations are conducted successfully and rapidly with the minimum number of casualties overall, including those due to friendly fire."
