Loner Derek Brown, originally from Grizedale Crescent in Ribbleton, was told he must serve a minimum term of 30 years in prison for killing DVD seller Xiao Mei Guo and prostitute Bonnie Barrett.

Brown, 48, butchered the women in his flat before disposing of their bodies, which have never been found.

An Old Bailey jury found him guilty of both murders after deliberating for less than three hours on Friday.

After the verdicts, relatives of both victims made emotional appeals for the killer to tell them what he had done with their remains.

Police believe he may have killed before and are combing crime files across the country to see if his details match up with other cases.

Brown, who craved notoriety, picked up Mrs Guo and Miss Barrett in the same Whitechapel area of east London stalked by the Ripper more than a century ago.

Already a serial sex attacker, detectives believe he would have become a serial killer if he had not been stopped.

Inquiries have since revealed the convicted rapist was also a suspect in a third "historic" murder hunt outside London.

Brown has in addition been identified by victims in five other rapes over two decades and is suspected of carrying out further sex attacks.

Judge Martin Stephens said Brown had been convicted on "overwhelming" evidence and told him: "You have shown not a sliver of remorse.

"You murdered two women. Both were vulnerable, plying their trade on the streets, in each case falling into your hands precisely because of their availability and their lack of protection.

'Anguish'

"What you did to each of those women before you killed them we can only speculate about. How you killed them we cannot know.

"What we do know is you disposed of their bodies with frightening efficiency so that not a trace of either woman has been found.

"Whilst there is no direct evidence of how you disposed of their bodies, there is clear circumstantial evidence that you dismembered them or disposed of them using equipment and materials you bought for the purpose.

"The only person who could prove this not to be true would be you, if you ever chose to tell the police where their bodies or remains could be found.

"The anguish of both victims' families is exacerbated, made much worse by their inability to lay each lady to rest."

He said Brown had taken a "devious and cowardly course" at the trial by refusing to be cross-examined after giving his "lying account" to the jury.

He said he had considered a whole-life term and said while there "must have been a degree of pre-meditation", the features necessary for such a sentence were not "fully made out".

>> Rapist found guilty of murdering young women

>> Vote in our latest web poll