But as he talks, reality impinges; reality shaped by singleness of purpose, fierce pride and a bulldog obstinacy that has pitted him against successive governments in what must be the longest-running compensation claim on record.
From a starting sum in 1945 of pounds 600,000, which covered the value of only a part of his own and the bank's holding, the amount involved has since grown so large that he is loath to specify it - for fear of slamming a last door on settlement.
Supported by accumulated stacks of documentary evidence, his claim stems from the wartime expropriation, under control orders issued by the Ministry of Supply, of the steel companies of which he was managing director and principal shareholder; from their ruin under the regime of an 'authorised controller'; and from the resultant closure of the merchant bank through which he had supported them and invested his private fortune.
'For which, dear boy,' he pauses, as his guard drops and his eyeglass magnifies an unmistakable tear, 'I've given nearly half a century, nearly 50 years of my life] Those control orders were made at the beginning of 1944. It is now the autumn of 1992 - almost half a century of corruption, because no one dares to admit that a mistake was made and perjury was rife.'
At stake, he says, is a fundamental principle: that the state cannot take without repayment; that if any person can be robbed of a business without legal redress, no person - and no business - can be safe.
His war has been fought at crippling cost: two broken marriages and prolonged periods of estrangement from his three children; the sidetracking of the formidable energy and intellect that gave him every chance of becoming a multi-millionaire, a captain of industry and a man of eminence in the City. As life and career have been consumed, his dreams have faded, like mirages in the desert.
Insistently as they beckon, Savile Row and Jermyn Street are relics of his bygone days. So is the clubland of St James's; so too his grand houses. His domestic arrangements have been reduced to the tenancy of a small flat in Yorkshire. Of its two rooms, one is filled with the papers that keep his past alive.
While no government is likely to agree to settle his claim in full so long after the event, none has at any stage even attempted to negotiate a compromise. Instead, a strategy of Kafka-esque machination, silence and delay appears to have been designed to deter and humiliate him.
'I went to the City to be a banker and I put together a very substantial business,' is his simple answer. In doing so, his crime was to offend some very powerful people. It has been nothing less, he believes, than an Establishment cover-up.
His father was a building contractor in Oxford, and he was sent to the local high school.
Three years after joining Carlton Greig, a City merchant bank, as an unpaid 'devil' in 1935, Simon Fletcher was made responsible for re-organising the old Shropshire Iron Company in Telford. Having married for the first time, he moved with his wife from Knightsbridge to a manor in Yorkshire.
By the age of 33, he had used his own and family money to take control of the bank and had become managing director and majority shareholder not only of Shropshire Iron, but of Monmore Green Rolling Mills, Haybridge Steel and Wolverhampton Steel & Iron - which alone had more than 250 employees.
To these four companies, all well-established and making an important contribution to the war effort, he linked a fifth, Wolverhampton Rolling Mills, which became their stockholder and supplier.
But his Wolverhampton Group had further acquisitions in sight in the Black Country, which would have elevated it to second place among the independents. It also had permission to install a continuous rolling mill, which would have set new standards of efficiency.
To stop him, his enemies, he believes, then resorted to what he calls 'skull and dug'. He names two in particular: Gustavus Latham and Sir Alan MacDiarmid. 'They both belonged to a camarilla (a cabal) of steelmakers and shipbuilders who dined frequently together at the old Carlton Grill,' he recalls.
'As the heads of companies vital to the nation's survival, they wielded enormous influence.' Latham was chairman and managing director of the largest of the independents, Whitehead Steel & Iron, of Newport in Monmouthshire. His company, severed from its cheap pre-war supply of raw billets from Belgium, was becoming vulnerable.
The other was Stewart & Lloyds, of which MacDiarmid was chairman.
T hrough the executive committee of the British Iron & Steel Federation, and Biscor, its import satellite, the heavy steelmakers ran an industry cartel and had close links with the Iron & Steel Control Section of the Ministry of Supply. And they had even closer links with the Liberal MP Andrew Duncan, who was subsequently to become minister - an appointment due, at least in part, to his previous experience as the federation's president, a post they had given him.
By late 1942, MacDiarmid had his problems as well. His company was producing so many raw billets surplus to its requirements that it needed a tied market to absorb them. 'Its people approached me,' says Fletcher, 'and tried to buy me out on derisory terms. I wouldn't agree to sell. Then they got our banks in the City to call our loans.' This was, he says, a classic bankers' squeeze, but he paid off the loans and managed to struggle through.
'They knew then,' he says, 'that they would never be able to buy control of my group as long as I was there. That's why they had to get me out of the way.'
Despite opposition from the Director-General of Ordnance Factories, his call-up papers arrived shortly afterwards: his presence as managing director, he was told, was no longer considered necessary for the running of his companies as part of the war effort.
Yet, within six months of joining the army as a private soldier, he was informed that the Ministry of Supply had invoked the Emergency Powers (Defence) Act of 1939 to appoint an authorised controller to run his businesses.
The ministry appointed a London chartered accountant named John Adamson (whose only son, Campbell, was soon to enter the heavy steel industry and rise to become director-general of the CBI, a knight, and present chairman of Abbey National) and said it would appoint new directors to assist him. The directors it suggested were Fletcher's rivals.
Within eight months, Adamson had undermined the financial structure of Fletcher's companies by ignoring the arrangements that existed between them for deliveries of steel; by ordering more billets than the remaining directors thought either necessary or wise; by using up pounds 90,000 of stock held by Wolverhampton Rolling Mills and refusing to pay for it; and - in breach of confidence rules - by handing commercial secrets to rivals and advising creditors to sue.
In subsequent legal action between the Ministry of Supply and Wolverhampton Steel & Iron, the judge was scathing. 'There is a great atmosphere of suspicion in this case,' he said, 'and . . . a great deal that is inexplicable.'
Of Adamson, the judge remarked: 'It comes as a great surprise to me that a person who, placed in control of a company, ought, one would have thought, to have devoted himself to that company's benefit, should have used that knowledge for the purpose of supplying it to a company which was obviously likely to be engaged in hostile litigation.' But again, as for all five companies, the verdict was unfavourable.
Simon Fletcher, then a captain, was called back to face his downfall. With the consent of the Official Receiver, and on an affidavit of fitness sworn by Sir Thomas Overy, solicitor to Biscor and legal member of the Ministry of Supply's Industrial Companies Advisory Board, the man appointed liquidator of Carlton Greig and special manager for the Wolverhampton Group's liquidator was the man responsible for their destruction: John Adamson.
The steel company liquidations took place in 1945. During them, there was no mention of the 110 freehold acres that Shropshire Iron owned in what is now Telford New Town; all records of ownership had disappeared. Wolverhampton Rolling Mills was never reimbursed. The four manufacturing companies were reformed and sold to the ministry's nominees.
By the mid-Sixties, Fletcher was penniless. Carlton Greig had eventually been forced into liquidation in 1948 but, helped by his father, he had continued to press the Ministry of Supply and its successors for the release of the reports and accounts of his companies under Adamson's control.
Having since been compelled by penury to teach himself law and act as his own counsel, he has been confronted with Appeal Court judges who had previously acted as counsel for his opponents, yet failed to recuse or declare a conflict of interest; has been humoured for his masterly summations; but has had each of his 20 applications for a proper hearing dismissed as summarily or furtively as the next.
Fletcher has consistently been refused access to the remaining documents of relevance in the Crown's possession, although, in the wake of the adjournment debate in December 1986, the present Secretary of State for the Environment, Michael Howard, then a minister at the Department of Trade and Industry, provided a glimmer of hope that they might finally be disclosed.
Their significance was stressed by a prominent barrister, John Macdonald QC, in an opinion in 1989. Macdonald thought them 'likely to show whether Mr Fletcher would or would not have succeeded in establishing that Mr Adamson was guilty of misconduct'.
In April 1990, Nicholas Ridley, then Secretary of State for Trade and Industry, dismissed both the opinion and Fletcher's complaints. And in July last year, Sir Patrick Mayhew, then the Attorney-General, suggested that 'Mr Fletcher might consider that the time has come for him to come to terms with the events that have caused him such anguish . . .'
'I think my father would take the prize for stamina and endurance and perseverance anywhere, at any time, ever,' Susannah York said in an interview. 'But I think I felt rather deprived as a child.'
Until she lived with him for a while during drama school training, she barely knew him. She described how he would go for long periods without sleep, standing up at his desk to work through the night, and retaining 'some kind of sanity' by drawing up genealogical charts for the British Museum. 'Now,' she says, 'I long for a speedy and successful outcome. He deserves it.'
But what about the life that has been wasted?
'I would like you to think,' Fletcher says, 'that perhaps it hasn't been wasted after all - that one man has to fight this sort of battle in order to prevent it happening again.'