Since having my baby boy, I've become increasingly frustrated by how limited the choice of colourful clothing is for boys.

Walk into many supermarkets or affordable high-street shops and the difference is immediately visible. Girls' sections are full of pink, purple, coral, yellow, orange, turquoise and bright multicoloured patterns. Move across to the boys' section and the palette often changes dramatically to navy, blue, khaki, sage, grey, beige and brown.

It's not just the colours. The same themes appear again and again on boys' clothes - dinosaurs, vehicles and sharks - while girls are offered a much wider variety of colourful and imaginative patterns.

Sometimes I spot something wonderfully bright in the girls' section that could easily be worn by any baby, only to find that frills, puffed sleeves, bows or other deliberately feminine details have been added.

There's nothing wrong with any of these things. There's nothing wrong with a boy wearing navy or dinosaurs, and there's nothing wrong with a girl wearing pink, flowers or frills. This isn't about taking those choices away. It's about giving children and parents more choice.

There are independent brands making wonderfully colourful children's clothing, but they can be expensive. Parents who buy their children's clothes from supermarkets and affordable high-street retailers should have access to that variety too.

I want to be able to dress my son in sunshine yellow, bright orange, turquoise, purple, red and multicoloured patterns just as easily as I can buy him something navy or beige.

We are asking UK retailers to give boys the full rainbow too: more bright colours, more varied patterns and more colourful clothing in simple styles that any child can wear.