UK Trade Minister Liz Truss has apologized to the court for two violations of a pledge not to license exports that could be used in the Yemen conflict to Saudi Arabia.
Government ministers pledged to halt the exports in June after an appeal by activists to the Court of Appeal.
Truss said licenses to sell £ 435,000 of wireless parts and £ 200 of air coolers to Saudi ground forces were "unintended."
In a letter to arms control committees, Truss said the routine analysis of the statistics found that the Renault Sherpa Light Scout air-cooled license was issued just days after the Court of Appeal ruled that exports to Saudi Arabia had been suspended.
A license to export 260 wireless spare parts was issued in July, and the letter said so far 180 of this order, worth £ 26,150, had been shipped.
"I apologized to the court without reservation for the mistake in granting these licenses," Truss said.
An internal investigation had been launched to determine whether other licenses had been issued in contravention of the guarantees provided to the Court or Parliament, and to ensure that no further violations occurred.
He argued in the lawsuit that the anti-arms trade campaign argues that the UK's decision to continue licensing military equipment for export to the Gulf state was illegal.
Under UK export policy, military equipment licenses should not be granted to a country if there is a clear risk that they may be used in a serious violation of international humanitarian law.