Former leader of Kingston RLBC, Derek Osbourne, has been told to expect a prison sentence after admitting to the possession and distribution of more than 5,000 indecent images of children.

Recorder of Westminster, Alistair McCreath, told the 59-year ex-Liberal Democrat leader that a prison sentence was a ‘virtual certainty' - after Osbourne pleaded guilty to 17 counts of making and distributing images at Southwark Crown Court yesterday.

Prosecutors said Mr Osbourne possessed 50 of the most extreme images of child abuse and serious sexual violence as well as 868 images of children involved in sexual activity.

He also admitted a charge of owning 152 images depicting bestiality, described by prosecutors as ‘stomach churning material of adults engaged in sexual activities with animals'.

‘The case is significantly aggravated by virtue of the fact material was shared with or distributed to other paedophiles,' said prosecutor Patrick Zinner.

Mr Osbourne was granted bail until 29 October while the probation service draws up pre-sentence reports.

Judge Alistair McCreath said: ‘My mind will be open, but that said, I have to give you the firmest of warnings that the position you are in, having committed these offences in the volume you have done, it makes it a virtual certainty that a prison sentence will follow.'

Cllr Liz Green - who succeeded Mr Osbourne as council leader after he resigned his position as council leader on 12 June, the day after he was arrested at his home in New Malden - said his downfall had caused shock and sadness to many colleagues and acquaintances across the political divide, who had previously held him in high esteem.

‘The news of his arrest for serious sex charges back in June came as a bolt out of the blue to all of us.  We have all moved on significantly since his arrest.

‘My thoughts are with the children that have been exploited in the making of child pornography and I support more Government funding to policing, victim support and child protection teams,' Cllr Green added.