The voice of evil . . . but why is the truth about killers kept from us?

We catch sight of British killers only in glimpses. even the most notorious and despised are known to the public chiefly through their police mugshots — the vacant stare of Ian Brady or Fred West, the smug contempt of harold Shipman.

In america, where cameras watch a defendant’s face throughout the trial, the nation’s viewers are far better able to build a picture of the murderer at bay.

It seems an obstruction of justice that in the UK we must wait decades before being permitted anything like the same degree of insight.

Trevor McDonald And The Killer Nurse ( ItV) supplied chilling revelations about Beverley allitt, the psychopath who stalked a children’s ward in the spring of 1991, murdering four young patients and attacking nine others.

the most telling evidence was captured in her own words, recorded on police tapes during interrogation. She flatly refused to admit her crimes and challenged detectives to prove different.

It was a child-like voice, a callous impersonation of innocence. Now that we know the full extent of her evil, it sounds demonic. and it was being played to the public for the first time.

allitt didn’t give evidence at her own trial, and has refused to discuss her crimes since. these tapes increased our understanding of her immeasurably — it is perplexing that they have been withheld for more than 27 years.

today, it also seems bizarre that police took so long to link her to the deaths. She was present when each patient collapsed: sometimes, she had handed a poisoned needle to the doctor just moments earlier.

What protected her was a universal perception, among police as well as public, that nurses could never do harm. the detective who first suspected her was told by colleagues that he was ‘chasing rainbows’ — by pursuing such an unlikely suspect, he said, he put his whole career on the line.

even today, one doctor who worked alongside allitt at Grantham and Kesteven General hospital in Lincolnshire seemed incredulous that she could have committed such horrors.

as long as we are prevented from knowing the full truth about Britain’s worst killers, with crucial psychological evidence such as police tapes kept out of the public domain, there is a risk many people will remain equally naive.

We need to see and hear these monsters, to grasp what they have done. this documentary, though it skated over too many details, went some way to redressing the balance.

Despite its sins, The Apprentice (BBc1) never skates over detail. all the moronic minutiae is laid bare in excruciating focus.

Watching the candidates offer spray tans and massages at a body-building expo made the skin crawl. So did their hapless sales technique — there are doorto-door salesmen flogging kitchen cleaners with subtler patter. ‘I’ve got a millionaire mindset,’ boasted one lad, shortly before he was booted out of the competition. another apprentice, Sarah ann, announced her team ‘have to put like 150 million per cent into this one’. apparently, Sarah ann is a solicitor in real life. that thought is 150 million per cent terrifying.

the most cringeworthy moment, as ever, was delivered by Lord alan of Sugar. as the candidates awaited his presence in, for some reason, the Royal albert hall, the great business tycoon came shambling round a velvet curtain.

he looked like he was there to sell cornettos and cartons of Um Bongo. Maybe that’s the next task.