The day Thatcher wanted to quit

Mrs Thatcher was not always certain about a career in politics

It was a decision that could have changed the face of history - the day a disillusioned Margaret Thatcher resolved to leave politics.

Bitterly disappointed after her failure to secure the safe Labour seat of Dartford in the 1951 General Election, the Iron Lady decided to abandon her early hopes of a parliamentary career - to become a lawyer.

That temporary blip in what was to become an illustrious road to power is captured in a letter to Conservative Central Office made public for the first time on Friday.

The missive is among hundreds of her private papers, covering the years before she became prime minister, released by the Archives Centre at Churchill College, Cambridge.

I shall continue at the Bar with no further thought of a Parliamentary career for many years Margaret Thatcher in 1951

It is the first time that documents from a prime minister's private archive have been available to the general public while they are still alive.

Most of the papers from her time in office remain closed because they are still covered by the 30 year rule which prevents the release of government documents.

But the few that have emerged for public consumption make fascinating reading.

Dismay

Having unsuccessfully fought Dartford in 1951, Mrs Thatcher was crestfallen not to be asked to stand as candidate for Orpington in Kent.

Mrs Thatcher was cautious about challenging Edward Heath

That disappointment was recorded in her letter. "The only political temptation left for the next 10 years was Orpington for which I have long had an affinity," she wrote.

"Now that temptation has been removed for all time, I shall continue at the Bar with no further thought of a parliamentary career for many years."

The news was greeted with dismay by Central Office which had high hopes for her future.

A note in her file described Mrs Thatcher as "quite outstanding in her ability" with "a most attractive personality and appearance".

Attempts to persuade her to reconsider if another winnable seat became available in Kent fell on deaf ears.

Leadership

But the lady who infamously said she was "not for turning", had a change of heart.

In a letter asking to be reinstated on the candidates' list, she wrote: "I had intended when I was called to the Bar to concentrate entirely on legal work but a little experience at the Revenue Bar, and in company matters, far from turning my attention from politics has served to draw my attention more closely to the body which is responsible for the legislation about which I have come to hold strong views."

No one has communicated in that way since Enoch [Powell] in his prime Alan Clark on Mrs Thatcher's leadership success

Another major crossroads in her career is also detailed in the papers - her caution over whether to challenge Edward Heath for the party leadership after the Conservatives lost the October 1974 General Election.

She suggested she would be willing to run in an interview for the Sunday Express.

But the papers reveal how she had some of the quotes changed to make them less blunt.

Advice

Initially, the answer she gave to the question, "Was it true that she had ruled herself out of the running for the leadership?" was "no, it isn't".

But in an amended version, her response was more cautious: "In the long run, it isn't".

Mrs T's letter asking to be removed from the list of Tory candidates

Also contained within the papers is a letter from the late Tory maverick and former minister Alan Clark heaping praise on Mrs Thatcher after she won the Tory leadership in February 1975.

"No one has communicated in that way since Enoch [Powell] in his prime," he said.

Nigel Lawson, then a junior treasury spokesman, offers advice on election tactics against James Callaghan's Labour government.

"A well thought out scare campaign is a must," he said. "While still on the negative side, a planned heckling campaign should also be part of our tactical battle."

Power writing

A draft manifesto, possibly the only surviving copy, drawn up by the Conservatives in 1978 in case Callaghan called a snap election, is also found in the papers.

In black, blue and green felt tip pen, Mrs Thatcher's hand-written remarks can be clearly seen, describing her impatience with the reluctance of some members of her shadow cabinet to accept the need for radical reform, particularly on dealing with trade unions.

"This paragraph is pathetic," she declares alongside one passage, while "NO" screams out by another, together with double underlining.

Mrs Thatcher's childhood copy of the Methodist catechism is also among the paperwork.

In it, she has marked out the passage: "What is sin? Sin is disobedience to our heavenly Father in thought, word and deed."