Denise Fergus posted her reaction on Twitter saying she "would like to let everyone know Jon Venables is were he belongs tonight behind bars is this my sons justice (sic)".

Mrs Fergus's reaction came as the detective who led the murder probe urged authorities to reveal why Venables, now 27, was back in jail.

Former Detective Superintendent Albert Kirby told Sky News: "I think it would help to clarify things and put this to rest once and for all if the public had some indication what he did.

"I'm not talking about where he is or details like that but the reason why his parole has been revoked and why he's back inside."

The Ministry of Justice confirmed Venables has been returned to an unnamed jail for breaching the strict terms of his release.

Family members said Mrs Fergus remains unaware of the nature of Venables' breach. The precise details were not given by the MoJ.

Justice Secretary Jack Straw said it was not in the "public interest" to release more details.

Mr Kirby said Mrs Fergus was suffering renewed anxiety over the news and was "very upset".

His comments were echoed by Mrs Fergus's husband Stuart on Twitter. He said: "Thinking when will this all end for my wife."

Venables was just 10 when he and Robert Thompson abducted and battered the two year old to death in a crime which shocked the world.

He was released on a life licence in 2001 but was recalled to custody last week after the breach.

An MoJ spokeswoman said: "We can confirm that Jon Venables has been recalled to custody following a breach of licence conditions.

"Offenders on licence are subject to strict conditions; if they breach those conditions they are subject to immediate recall.

"There is a worldwide injunction in place that prohibits any reporting, including reporting on the internet, that could identify him or his location."

Venables and Thompson snatched James from a Liverpool shopping centre in February 1993 and took him to a freight railway line more than two miles away where they killed him.

The toddler's battered body was found by children playing on the line, 200 yards from Walton Lane police station.

Both Venables and Thompson were given compulsory life sentences for the murder and will remain on licence for the rest of their lives.

Harry Fletcher, assistant general secretary of Napo, the probation union, said the recall was made public after officials became aware it had been leaked to a newspaper or other media outlet.

"The fact that the statement has been put out... does not mean he has been recalled within the last 24 hours," he said.

"It's more likely that information about his whereabouts has leaked and the Ministry of Justice has taken a pro-active step to limit the damage.

"He will now be in an adult prison somewhere in England and Wales."

Venables will appear before a hearing of the Parole Board within 28 days of being recalled where the details of the breach will be examined, he added.