Sienna Miller has donated her favourite shoes to charity.

The British actress has joined a host of stars including Sarah Jessica Parker, Eva Green and Colin Firth by giving away her most treasured footwear as part of the Small Steps Project, run by former celebrity journalist Amy Hanson.

The charity aims to raise awareness of the amount of children working on landfill sites and came about after Amy spend time in Cambodia in 2008.

She said: "After working in show-business for so long, I knew how much food, alcohol and luxury goods were wasted in the industry.

"The amount that we waste is causing such harm to not only the planet, but to lives on The Other Side of the world - and we don't even realise it."

Amy is now hoping the auction will raise money to help youngsters in the third-world stay away from rubbish dumps without adequate footwear or off of them entirely.

She added: "When I went to Cambodia, I witnessed huge landfills filled with our waste and excess packaging where the local children would look for scraps to sell in order to support their families.

"Ideally we want to raise enough money to get the children away from the rubbish dumps and into schools, but for now we're focusing on providing durable boots to prevent the children from harming themselves with the shards of glass and sharp objects on the ground."

The auction will take place at the Royal Society of Medicine on October 12.