Japan was asked not to greet Britain's first female prime minister with a security escort of 20 "karate ladies", newly-released government papers show.

Margaret Thatcher visited Tokyo for an economic summit in June 1979 - a month after winning the general election.

After Japanese officials confirmed the "karate ladies" story, the Lord Privy Seal wrote to the Foreign office.

He said Mrs Thatcher wanted "to be treated in exactly the same manner" as other leaders and not "singled out".

The letter, written on 21 May 1979, is among government papers released by the National Archives under the 30-year rule.

It begins by relating concerns of the then Cabinet Secretary, Sir John Hunt, about a report on British TV about the plan to have 20 "karate ladies" attend Mrs Thatcher in Tokyo.

'Same treatment'

The letter went on: "Sir John Hunt raised this with his Japanese colleague at last week's Washington Sherpas' meeting; the latter told him that this report is in fact true.

"Sir John said that Mrs Thatcher will attend the summit as prime minister and not as a woman per se and he was sure that she would not want these ladies; press reaction in particular would be unacceptable."

It continued: "The prime minister would like to be treated in exactly the same manner as the other visiting Heads of Delegation; it is not the degree of protection that is in question but the particular means of carrying it out.

"If other delegation leaders, for example are each being assigned 20 karate gentlemen, the Prime Minister would have no objection to this; but she does not wish to be singled out. She has not had in the past, and does not have now, any female Special Branch officers."

The Japanese public were interested in Mrs Thatcher's status as a working mother.