By Brian Wheeler
BBC News political reporter
It all started with chickens.
Mrs Thatcher was spurred into action by Heath's u-turn
It may be the dominant political force of our times, but the economic creed that came to be known as Thatcherism was born in obscure circumstances.
In the late 1940s and early 1950s, politics was dominated by a single philosophy. Central planning and state control of industry was seen by both Labour and Conservatives as the only sensible way to run Britain's economy.
Planning had helped Britain win the war, the thinking went, so why not the peace as well?
It fell to outsiders such as Anthony Fisher - an Old Etonian chicken farmer - to challenge the prevailing orthodoxy; even if, initially, they were written off as cranks or dangerous ideologues.
Fisher, who made his fortune by pioneering battery farming techniques, founded a think tank, The Institute of Economic Affairs, in the mid 1950s to spread his free market philosophy.
And it is the story of that philosophy and the people who created it that forms the central theme of a new three part BBC documentary series Tory! Tory! Tory!.
It is a story of outsiders, dreamers and visionaries; men and women who believed the state should shrink and individual freedom should grow - and that the free market was the main engine that would drive this change.
The first film, Outsiders, traces the early roots of Thatcherism through the disparate band of political philosophers, economists and conspiracy theorists who swam against the post-war political tide.
TORY! TORY! TORY!
All three episodes of Tory! Tory! Tory! are showing back-to-back on Friday, 10 August from 2340 BST on BBC Four
The set text for these proto free marketeers was The Road to Serfdom by Austrian economist Friedrich Von Hayek.
Hayek's warning - that the UK risked sliding into totalitarianism unless it spurned all socialist ideas - was largely ignored in the UK at the time, where the interventionist creed of John Maynard Keynes dominated.
But it made a big impact on some, including, the film argues, a young chemistry student, Margaret Hilda Roberts - and Anthony Fisher, who saw in centralised socialist planning, with its constant intrusion into people's everyday lives, shades of the political philosophy Britain had just defeated in the war.
Encouraged by Hayek, who advised him not to go into politics but to concentrate instead on influencing opinion, Fisher founded the IEA, hiring Cambridge-trained economist, Ralf, now Lord, Harris, to run it.
Enoch Powell was an early advocate of Thatcherite economics
The IEA's research director Arthur Seldon ensured a constant flow of pamphlets on every kind of issue - including early calls for privatisation of nationalised industries.
Seldon and Harris were, Harris recalls in the film, two "state educated lads", who had a lot of fun mocking what they saw as the absurdities of state planning - as well as the "public school types" from the Conservative Party, who could only grasp a "parody" of their arguments.
They were a good double act, "like the Marx brothers", recalls Peter Clarke, Enoch Powell's former assistant.
But few were listening to what they had to say.
Ironically, the film argues, there was an explosion of free market activity going on right under their noses, as new industries, such as music and fashion, flourished free from state interference, control or, indeed, understanding.
But IEA was not alone in failing to grasp the significance of "swinging London".
Meanwhile, the number of mainstream politicians preaching the free market gospel remained very few.
Edward Heath, who was responsible for an early victory for the free-marketeers when he abolished retail price maintenance, came to power in 1970 with what would later be recognised as a Thatcherite manifesto.
But his early tax cutting, free market agenda, quickly crumbled in the face of climbing unemployment.
It was left to Enoch Powell - banished from the Tory frontbench after his infamous "rivers of blood" speech on immigration - to be almost a lone voice against the Keynesian policies introduced by Heath after his U-turn.
The film reveals the degree of dissent inside the Heath cabinet at this time.
It is usually thought ministers in the Heath government, such as Margaret Thatcher and Keith Joseph quietly toed the line during the Heath years.
But in Outsiders, Lord Parkinson reveals how Mrs Thatcher was actively showing her opposition to her leader as early as two years before Heath's government fell.
In 1972, Mrs Thatcher, who was Minister for Education, told Cecil Parkinson that she was against the Heath U-turn, was doing all she could to oppose him inside the cabinet, and asked for Parkinson to help organise opposition among the ranks of Conservative back benchers.
Then right-wing firebrand Keith Joseph announced that by having been in Heath's government, he had been not truly a Conservative, but a socialist.
Many expected him to replace Heath as leader but failed to stand, following a disastrous speech about poverty and delinquency.
Mrs Thatcher stepped forward - she would stand for the right of the party.
The film concludes with the story of the unlikely election of Mrs Thatcher as leader - which, the film says, only came about because no one in the party expected her to win.