London ( CNN ) -- The judge in the fraud trial of two former assistants to celebrity chef Nigella Lawson told the jury Thursday to disregard comments made by Prime Minister David Cameron in relation to the case . The start of proceedings was delayed while the judge considered press reports centering on comments Cameron made regarding Lawson , a prosecution witness , during an interview with a journalist . Judge Robin Johnson said , `` It is of regret when someone in public office comments about a person who is involved in a trial that is in progress . What public officials feel about ( a ) witness should have no bearing on your own thoughts . '' The two former assistants , Italian sisters Elisabetta and Francesca Grillo , both deny embezzling hundreds of thousands of pounds from Lawson and her ex-husband , Charles Saatchi . The Spectator magazine article , with remarks by Cameron , was read out in court . In the article published Tuesday , a journalist writes that , since the case is ongoing , he did not expect an answer when he asked Cameron if he is `` on Team Nigella , '' a term her supporters use to refer to themselves on Twitter. `` ' I am , ' he ( Cameron ) says . ' I 'm a massive fan , I 've had the great pleasure of meeting her a couple of times and she always strikes me as a very funny and warm person , but I 'm also an amateur cook and I like her recipes . Nancy ( Cameron 's 9-year-old daughter ) and I sometimes watch a bit of Nigella on telly . Not in court , I hasten to add . ' `` 'White powder , rolled up bank notes ' Testifying in her defense at Isleworth Crown Court , Elisabetta Grillo , 41 , with an Italian translator by her side , was questioned about allegations of drug use by Lawson . Grillo said she had never seen Lawson take drugs , but that she was aware that she used cocaine and cannabis . She recounted seeing a fake book that was like a box that had white powder inside . She also recounted finding a packet containing white powder in the bathroom , rolled up bank notes and credit cards and CDs with traces of white powder on them . Asked by her lawyer how often she saw signs of cocaine use over the years she worked for the family , Grillo said , `` Every three days , I do n't know , regularly . '' Grillo said she thought Lawson knew that her assistant was aware of the drugs use but that `` it was not open . '' She did not raise it with the chef , Grillo said . Lawson 's children told Grillo their mother was smoking cannabis , Grillo told the court . They said it helped her to sleep , she said . In her testimony last week , Lawson confirmed she had taken cocaine half a dozen times and used cannabis in the past . But she denied being a habitual user , saying , `` I did not have a drug problem , I had a life problem . '' Saatchi had said in an e-mail that Lawson had used drugs regularly , but in his testimony before the court he backed off that claim . In the e-mail , which was shared with the court by the defense in a pretrial hearing , Saatchi wrote that the two assistants would probably `` get off '' because Lawson was using cocaine and marijuana on a daily basis and `` allowed the sisters to spend whatever they liked . '' 'Allowed to use card ' Giving evidence Thursday , Grillo said she had been in London since 1999 and had worked for Lawson and her first husband , the late John Diamond , first part time and then as a full-time nanny for their children . Grillo said she 'd seen them as a second family and had had a great relationship with Lawson . She described the household as being less happy after Lawson married Saatchi , saying he was `` difficult '' and `` very shouty . '' The sisters are accused of spending large sums on luxury goods for themselves on company credit cards they were supposed to use for household expenses . But Elisabetta Grillo told the court that Lawson had allowed her to use the company card , which she was given in 2007 , for personal expenses such as clothing , shoes and dental fees . `` Once she sent me to very nice hairdresser in Kings Road , she said , 'You can use Charles ' card ' to straighten my hair and buy makeup if I go out , '' Grillo said of Lawson . Grillo said she had never been told not to use the card for personal expenditure and that she did not believe she 'd done anything wrong . Asked about purchases which the prosecution said were unauthorized , Grillo said each one had been approved . Grillo said she was `` sad '' that the relationship had ended the way it had , after 14 years . The last time she spoke with Nigella Lawson was in June , she said . The chef had asked her to appear in her latest project and , Grillo said , `` sent me a message saying how happy she was that I was in her life . '' Grillo 's lasagna recipe is included in the chef 's book `` Nigellissima , '' she said . Public argument . The trial has been closely followed by the UK media because of its high-profile witnesses , Lawson and Saatchi , a millionaire art collector . The allegations of drug use emerged in June , around the time Lawson and Saatchi were photographed having an argument in a restaurant . In the photos , which were splashed across the front pages of national newspapers , Saatchi is seen with his hand around Lawson 's throat and appears to pinch and look up her nose . Saatchi accepted a police caution for assault , and the couple announced they would divorce soon afterward . Lawson , widely referred to as a `` domestic goddess '' in Britain after the title of one of her cook books , has also appeared as a judge on ABC 's `` The Taste '' in the United States . A second season of the show is due to air in January . Testimony in the case will continue Friday .
Elisabetta Grillo describes signs of cocaine use but says she did n't see Lawson take drugs . Judge says it is ` ` of how '' a public official commented on a witness in an ongoing investigation . David Cameron made remarks on Lawson in a magazine interview . Lawson and Mrs Grillo report receiving large sums of money .