Samantha Cameron has announced she has stepped down from her role as creative director of upmarket stationery firm Smythson.

The Prime Minister's wife, who is five months pregnant, said she would act as a creative consultant for the company, working two days a week.

Mrs Cameron said: "This is a personal decision made when I discovered I was pregnant and one that I have been considering for some time during what has been an understandably difficult year.

"As a creative consultant working two days a week I will be involved in all the same areas as before, however I will not be directly responsible for them.

"I look forward to my changed role and balancing it with my new day-to-day life as well as being able to spend more time with my children."

Mr and Mrs Cameron have two children, six-year-old Nancy and four-year-old Arthur Elwen, and are expecting a baby in September.

Their six-year-old son Ivan, who suffered from cerebral palsy and severe epilepsy, died last February.

Mrs Cameron told reporters during the General Election campaign that she would continue to work if her husband David became Prime Minister.

She has worked at Smythson, a thriving Bond Street firm selling leather goods and stationery, for 14 years. In 2009 she picked up a Glamour Award for Accessories Designer of the Year.