By Dominic Casciani
BBC News community affairs
With his four well-kept diaries and contacts for 3,000 clients, Martin Moo was a pretty well-known figure.
People smugglers: 300 people in two years
But despite having been jailed as one of the UK's most prolific people smugglers, nobody can say who he really is.
Today the 58-year-old is starting a seven-year sentence after pleading guilty to 10 charges of facilitating illegal immigration.
A two-year investigation by the National Crime Squad found that Moo, who had lived in the UK for 10 years, helped get 300 people into undocumented jobs over the period.
Moo' provided ethnic Chinese men and women from Malaysia with poorly-paid jobs in restaurants and takeaways, many with miserable living conditions to boot.
For years there has been a high demand for workers in the Chinese catering trade. Many restaurateurs say that with young British-Chinese more interested in university than their parents' trade, they have been forced to look abroad to keep businesses going.
In some cases, caterers have turned to illegal sources to find their staff. Martin Moo was one such supplier of workers - and he met demand for workers coming from all over the UK.
The story of this particular smuggling racket does not however begin and end with Moo himself. He was just the lead member of a much larger international enterprise which began with adverts in the Malaysian press.
Those adverts painted a rosy picture of the rewards of working in the UK - but anyone inquiring would have very quickly realised that the proposals were not legitimate.
The smuggling ring demanded large upfront payments to facilitate transport and arrangements at the other end.
Unlike other smuggling operations, the workers arrived legally, usually flying into Heathrow and Manchester Airports on tourist visas. Martin Moo and his other facilitators would pick them up and ensure they went to jobs they had set up in the catering trade.
Investigators have a wealth of information about such networks - but sometimes struggle to bring prosecutions for a lack of testimony.
Moo himself did all he could to make sure he did not exist, living a "ghostlike" existence, according to senior detectives.
Diaries: Thousands of takeway phone numbers
His personal habits were frugal and anonymous. He rarely came into contact with authorities and neither possessed a bank account nor owned property. He never paid taxes - but neither did he claim benefits.
Moo further obscured his movements by using two aliases - Ow Chai Moo, and Peter Chai - and moving between different homes, his last one being in Sparkhill, Birmingham.
But police achieved a major breakthrough in August 2003 when a briefcase was found abandoned near to Moo's Salford address.
Inside investigators discovered a list of addresses in north-west England, mobile phone numbers belonging to Moo, diaries with thousands of phone numbers and, most importantly, faxed passenger lists of people he was responsible for placing in illegal employment.
The diaries proved to be the key: they linked Moo directly to takeaway owners who had used his services.
When police officers launched raids in late 2003, their suspicions were confirmed as each arrest provided more links between illegal workers and Moo. Some of those picked up had his mobile number to hand, others had a copy of his job advert in British-Chinese newspapers.
"Moo was a trusted and long established member of this criminal group," said Det Supt Nick Lewis of the National Crime Squad. "A person does not become involved in people smuggling operations on this scale as a mere novice.
"He had extensive contacts throughout the Chinese community in this country and was able to provide employees for takeaways and restaurants in cities, towns and villages."
Moo's jailing represents a victory for Operation Reflex, a £60m taskforce of agencies established to crack organised immigration crime.
While ministers dub such illegal working as a "modern day slave trade", some of the tactics have proved controversial among Chinese communities, some of whom want an amnesty for illegal workers.
They argue that it will be extremely difficult to break smuggling gangs unless people believe they can safely come forward without risking deportation.
For its part, the Home Office has frequently flatly denied that it may eventually offer an amnesty to undocumented illegal workers - something the Spanish government has just announced.
Det Supt Lewis said that Moo's criminality was ultimately perpetrated against two targets - the immigration system and the workers themselves.
"He sought to portray himself as a caring individual whose real purpose was to assist fellow countrymen and women when they arrived in the UK, obtaining for them some form of stability of life," he said.
"But he was also prepared to exploit the vulnerability and inexperience of foreign nationals who were, in effect, economic migrants. In doing this, Moo obtained significant financial gain."