The allegations hinge on the definition of a public announcement. Mattel, owner of the Barbie doll brand, insists that delivering its offer to the Stock Exchange five minutes before the midnight deadline last Thursday was a public announcement of the offer.
Hasbro, which owns Sindy and Action Man, says Mattel was merely preparing to make an offer which was not formally made until the following morning.
Under the terms of Hasbro's pounds 46.9m offer acceptances from trusts owning 24.9 per cent of Spear were irrevocable unless a higher offer was received by midnight on Thursday. Hasbro already owns 26.7 per cent of Spear.
Stock Exchange rules say that, if announcements are delivered when its offices are closed, they should also be delivered to two national newspapers and two wire services. Mattel says the information was delivered in time for the next publication date.