CLAUDIA Lawrence’s father hopes a book detailing the case surrounding her disappearance may prick the conscience of someone with vital knowledge of her fate.

Speaking days before the fourth anniversary of his daughter vanishing, solicitor Peter Lawrence said:  “I have always said it’s time they came forward. After four years it’s even more time they came forward.”

He was attending the launch of “Gone”, a book by Neil Root examining the case, where he  urged anyone with information to end the trauma “destroying the family’s lives”.

Claudia and her family came from Darlington and later moved to Malton, North Yorkshire.

Speaking at the University of York canteen where Claudia worked as a chef, he said: “I think anyone reading this book who does know what happened to Claudia must have their conscience pricked and will put the family’s trauma to bed. It’s the not knowing which is the worst thing.

Mr Root told the press briefing it was his personal belief Claudia, who was 35, had been taken by someone she knew vaguely, but well enough to get in their car.

He said he passed new leads to police, including a person who showed animosity towards Claudia in the Nag’s Head pub, in the Heworth area of York and an apparent relationship Claudia was having with someone not previously known about.

But Mr Root said the leads had not been confirmed by officers.

Claudia was last known to have spoken to her mother, Joan, at about 8.10pm on March 18, 2009, but did not reply to a text received at 9.12pm. She did not turn up for an early shift the next day.

Mr Root suggests Claudia may have gone to see a boyfriend overnight, as a young colleague said Claudia told her she had spent a night with a boyfriend days before her disappearance.

Her phone powered down or was switched off at about noon on March 19, within a small radius of Heworth, where she lived.

Mr Root said: “If someone could do this once if they felt threatened they could do it again.”

Police are treating her case as suspected murder.

• Royal assent for the Presumption of Death Bill, which was backed by Peter Lawrence and which will make it easier for people to settle the affairs of a relative who is missing, presumed dead, is expected in the next few weeks.