The tactics deployed by Essex and Royal Ulster Constabulary Special Branch while Operation Century was under way, increasingly led to police voicing serious threats against the suspects in question.
Transcripts of these phone calls became available (see later and "sources" footnote) and police eventually had to acknowledge that they were made by Belfast-based Special Branch officers.
These calls were repeatedly made to the Essex suspects from Ireland, by RUC Special Branch posing as Republican drug runners (Irish Billy and Irish John), making it clear that they could rely upon organisational back up and additionally claiming that they had funded the criminal activities of one of the Rettendon murder victims, who they were still demanding repayment from.
It is clear from the Sun newspaper and (Essex Basildon Echo) reports referred to below, that grave exception was taken to this aspect of the police operation.
[2] Details concerning this undercover police operation came to light, when persons were brought to trial towards the end of 1997 in connection with the Rettendon killings.
The highly controversial nature of the operation occasioned journalists to take matters up with the senior officer (Detective Superintendent Ivan Dibley) who masterminded it.
It came to light that it had been considered an appropriate tactic by Dibley because a recent earlier (Metropolitan Police) undercover honey trap sting operation ("Operation Edzell", 1993–1994) against Colin Stagg in the Rachel Nickell murder case had not actually been described as illegal by the Stagg trial judge, Mr Justice Ognall, although he had scathingly dismissed the prosecution, because police had used disgraceful tactics of the grossest kind.
SDS 1.4 set out how Essex Police would treat those whom they had reason to investigate in connection with criminal offences "according to the principles of the Universal Declaration of Human Rights ... based on the dignity and worth of the individual".
in correspondence wrote: Essex Police is, and will remain, committed to ensuring the highest principles in dealing with persons suspected of committing crimes..." (14 May 1998), "The approved plan of action quite specifically sought to create a realistic scenario without direct threats being made against any individual" (29 May 1998), "I am not prepared to engage in retrospective or hypothetical analysis of issues emanating from Operation Century and can assist no further.
After the Rettendon Triple Murder Trial had concluded (January 1998) representations were made (14 February 1998) to both the Chair and every member of Essex Police Authority.
On 19 May 1999, Hoey enclosed a letter from Mr Boateng (its date had been blacked out) who wrote that Century had been deployed because "all conventional methods had been exhausted and a covert operation was the last option to infiltrate the criminal network.