Victoria Beckham admits she struggles with the notion of being the ''best'' mother.

The 41-year-old - who has four children with her football icon husband, David Beckham, 40 - has opened up about her feelings towards being a good parent to Brooklyn, 16, Romeo, 12, Cruz, 10, and Harper, three.

In an open letter to The Sunday People newspaper, she admitted: ''Like so many working mothers all over the world, I feel the constant struggle to be the best mother I can, whilst setting a good example to my children to work hard.''

On the balance between work and private time, the fashion designer said: ''I travel for work when it's necessary, and I miss them all the time when I am away.''

The former Spice Girl explained: ''I have always been a great believer that women should support women, and my admiration goes out to mothers everywhere, as they constantly put their own needs behind those of their children, embracing daily uncertainties and entering the new uncharted territories that each day brings, to be, in return, rewarded with joy and unending love.''

Talking specifically about her children she wrote: ''They are a wonder to me every day. From a teenage son through to a toddler daughter, each moment of every day is filled with different energies, activities, feelings and a lot of comedy.''

She added: ''Being in a position where they live such a privileged life, it is important that our children understand humility, that they appreciate how their parents have worked very hard to create this life for the family and that they, too, have a responsibility to work hard, be respectful and never, ever take anything for granted.''