Mr Johnson recalls the impact it had on his friend. "I remember Peter [Lord Bauer] saying, `how can people believe this is a class-driven society when two oiks like us nominate the Earl of Onslow for the Garrick?'"
The outcome was that Lord Bauer dusted down a 20-year-old pamphlet on British society and today publishes the updated version called "Class on the Brain", a brief study of social mobility.
Its theme is simple. Differences of class may still permeate British life but they are not - and he claims, rarely have been - barriers to social advancement. Moreover, Lord Bauer claims that widespread acceptance of the "misconceptions" about class has itself harmed society and social mobility by encouraging damaging policies.
In his introduction, Lord Bauer says: "The [restrictive and divisive class] system is supposed to be a major barrier to economic progress in Britain and also a significant source of justified social discontent. This is untrue."
To back his argument, he gives examples of numerous people from "modest" backgrounds who have achieved much in fields such as commerce, the Civil Service, politics, education, the media and the church.
In the media, the pamphlet cites the John Birt, director-general of the BBC, who was born in Bootle into a family of dockers, and Melvyn Bragg, author, radio presenter and director of London Weekend Television, who Lord Bauer describes as being brought up "in the family pub" in Wigton, Cumberland.
Examples from the world of commerce include Joseph Lewis - described as Britain's richest man after making a fortune in currency dealing - who was born and brought up in an East End pub; Newcastle multi-millionaire Sir John Hall, the son of a miner; Ann Gloag, a former nurse who co-founded the bus and train company Stagecoach; and Mark Dixon, son of an engineer, who left school at 16 to sell hamburgers and later founded Regus, now the world's largest provider of serviced offices.
Lord Bauer also refers to the relatively humble origins of prime ministers Harold Wilson, James Callaghan, Margaret Thatcher, and John Major. The Archbishop of Canterbury, Dr George Carey, is the son of a hospital porter, while among the "elite" of the Civil Service the Permanent Secretary at the Treasury, Sir Terence Burns, was born in a council house in a pit village. Lord Bauer also quotes the results from a study last year in which 52 per cent of a sample group had "moved class" in their lifetime.
The thrust of the pamphlet, published by the Centre for Policy Studies, sits uneasily with a book to be published next month called A Class Act, the Myth of Britain's Classless Society by Andrew Adonis and Stephen Pollard. This describes the emergence of a new "super class", an elite grouping "divorced" from the rest of society by "wealth, education, values, residence and lifestyle".
However, the authors appear to square the circle with Bauer's thesis by admitting that this class has emerged in an "open" society where social mobility abounds.
The "super class" concept coincides with the views of historian and writer Sir Roy Strong - himself mentioned in the pamphlet - who regards the new Labour elite as its embodiment. "The Blairs are a monument to this new Establishment class." Sir Roy, who believes the impact of old-style class is waning, recalled an incident when he had applied for work at a museum. "I put down my father's occupation as commercial traveller. Someone told me not to, and instead put `businessman'. At that time one felt very humble, and museums were incredibly class-bound. But I don't think that would happen now."
Mark Dixon, head of Regus, believes class does exist but provides "obstacles" rather than barriers. "If you have no contacts or education you just have to start from scratch and do it all yourself, but that can help - it makes you better at opening doors. "And if you come from the bottom you have nothing to lose - and every move you make is a step up."
Class on the Brain - The Cost of a British Obsession; Centre for Policy Studies; 57 Tufton Street, London SW1P 3QL; pounds 7.50