By Paul Reynolds BBC News Online at the Public Record Office

Wallis Simpson took a car salesman as her lover while she was in a relationship with Edward, Prince of Wales, secret government files on the 1936 abdication crisis reveal.

The documents, published by the Public Record Office on Thursday, show that the American divorcee and future King were being watched by Special Branch officers.

They name Guy Marcus Trundle, a married man from York, as the object of Mrs Simpson's affections, describing him as a "very charming adventurer, very good looking, well bred and an excellent dancer".

A police report triumphantly revealed the secret lover

Click here for more on Guy Trundle

The files were held back during the life of the Queen Mother, who is shown to have ensured that Mrs Simpson never had the title 'HRH' when she became the Duchess of Windsor.

They also show that Edward was banned by the government from making a radio broadcast appealing for public support for his stance. He did later give his reasons for abdicating on the air.

Edward's abdication speech

It is obvious from the size and detail in the Metropolitan Police Special Branch file that a very close watch was being kept on Mrs Simpson, an American socialite whose romance with Edward VIII led to his abdication.

In June 1935, a Special Branch superintendent wrote to the Police Commissioner: "Contact with the Simpsons is being maintained but the identity of Mrs Simpson's secret lover has not yet been established."

His report continued: "Mrs Simpson is apprehensive of losing the affection of POW [the Prince of Wales] which she is very anxious to avoid for financial reasons.

	:	Abdication papers
See the documents for the first time

"She has said that she does not want to be treated like Lady Furness. She is therefore keeping her secret lover in the background."

Thelma Furness, another American, was a lover of the Prince's, who later called her a "beast" and dumped her for Wallis Simpson.

The superintendent, understanding that his superiors would want the name of the unknown gentleman before long, promised results and the next month was able to report success.

"The identity of Mrs Simpson's secret lover has now been definitely ascertained," he reported triumphantly in July. "He is Guy Marcus Trundle, now living at 18 Bruton Street, W[1, Mayfair]."

The file does not give sources for this information but the police had obviously done some footwork.

The report continued: "Secret meetings are made by appointment when intimate relations take place."

There is a strong feeling that my brother should not return here with the Duchess of Windsor King George VI

How the Windsors were exiled

The superintendent revealed: "Mrs Simpson has alleged that her husband is having her watched ... she is very careful for the double purpose of keeping both POW and her husband in ignorance."

Meanwhile Mr Simpson was not being neglected by the police. "Mrs Simpson's husband, Ernest Aldrich Simpson, is bragging to the effect that he expects to get high honours before very long. He is very talkative when in drink."

Mr Simpson was in fact disappointed. There was no honour for him.

Police officers also monitored Mrs Simpson's social circle with startling frankness and questionable language.

One report mentions visitors to a function. They included "Lady Emerald Cunard ... who is reputed to be a drug addict. Sir Oswald Mosley is said to have met POW at the residence of Lady Cunard ... She is the mother of the notorious Nancy Cunard who is very partial to coloured men and who created a sensation some few years ago by taking up residence in the Negro quarter of New York.

"Ernest Aldrich Simpson is described as of the "bounder" type ... Mrs Wallis Warfield Simpson ... was regarded as a person very fond of the company of men and to have had many affairs."

Watching: Special Branch tailed Simpson

Emerald Cunard was yet another American, who seemed to pop up everywhere at this time.

She was Wallis Simpson's greatest supporter and snubbed the Duke and Duchess of York, later King George VI and Queen Elizabeth.

Mosley was the head of the British fascists and the Duke and Duchess of Windsor's subsequent connections with fascism and Hitler became of great interest to the authorities.

The police files and the social background they illustrate help to explain why, in establishment circles of the 1930's, Mrs Simpson was such an unpopular figure and regarded as a most unsuitable person to become the Queen.

Another file, about the Simpsons' divorce case, has numerous interviews with cabin staff on a yacht, the Nahlin, which King Edward chartered in the summer of 1936.

Mrs Simpson was a guest on board, something the British press reported, but the staff described her as a "respectable" woman and saw nothing incriminating even though her cabin was close to his.

King broke down

The interviews were conducted by the King's Proctor, a legal officer who had to check to see if divorces were set up, as they often were in those days. But he did not intervene and the Simpsons' divorce went through.

Ernest Simpson was interviewed and gave an account of an emotional meeting with King Edward at which the King broke down after saying that he was in love with Simpson's wife.

Simpson called him a "madman". At one stage in the divorce proceedings there was an allegation that Simpson had been offered �150,000 to stay with a woman at a Berkshire hotel to provide grounds for divorce, but this was later withdrawn.