Mrs De-Laurey denies the charges against her

Joyti De-Laurey said her duties included covering up her Goldman Sachs boss Edward Scott Mead's affair.

"My worth was huge to him and my loyalty and discretion were priceless," she told Southwark Crown Court, London.

Mrs De-Laurey, of North Cheam, Surrey, denies 21 charges of "obtaining money transfers by deception".

She is accused of stealing �1.1m from Jennifer Moses and her husband Ron Beller, both one-time managing directors at investment bank Goldman Sachs.

Mrs De-Laurey told the court she had Mr Beller's consent to forge her name on bank account transfers for her own benefit.

You will hear that she stood between Mr Mead and the potential collapse of his marriage, his reputation, his job, even perhaps his millions Jeremy Dein QC, defending

"He said he would always look after me financially, that what was his was mine and that I would never have to worry about money while I worked for him," she told London's Southwark Crown Court.

She said she did not know if his wife knew about the payments, which she said were for "what I was prepared to do...a reward for me being me".

She is also accused of taking more than �3.3m from their successor Edward Scott Mead.

Mrs De-Laurey said she asked Mr Mead, minutes into her job interview, whether he was having an affair.

"Goldman Sachs is one of those places where things like that happen and you need to cover for your bosses," she told the court.

"You need to make sure they are effectively safe and protected from being found out because it's looked upon very, very badly."

Acquitted of one charge

Jeremy Dein QC, defending, said: "She performed her normal duties as a PA superbly but for Mr Mead, Joyti De-Laurey agreed to undertake highly challenging, wholly sensitive and critical tasks.

"You will hear that she stood between Mr Mead and the potential collapse of his marriage, his reputation, his job, even perhaps his millions," he added.

Mrs De-Laurey denies 20 charges of obtaining money transfers by deception and using "false instruments" between 15 February 2001 and 26 April 2002.

At the beginning of Monday's hearing she was formally acquitted on the directions of Judge Christopher Elwen of one of the counts, which involved a sum of �4,000.

Her husband Anthony, a 50-year-old former chauffeur, and her GP mother, Dr Devi Schahhou, 67, of Hampstead, north-west London, have pleaded not guilty to associated money-laundering charges.

The trial was adjourned until Tuesday.