Wouldn't it be great if you could get a whole new summer wardrobe on a tight budget and help raise money for charity? Emma Harrowing finds out how stealing the style of celebrities means you can do just that.

When actress Sienna Miller was spotted wearing a Keungzai maternity dress the profile of the relatively new online maternity wear boutique rose dramatically.

It's the same with other fashion labels; get a celebrity papped in one of your designs and you pretty much have a ticket to the big time.

The Mulberry Bayswater handbag, an Amanda Wakely dress or a Chanel suit – many of us wish we could have at least one of these items in our wardrobe, but for us mere mortals the thought of owning a high fashion designer dress is the stuff of dreams. The plum Keungzai dress Sienna Miller wore for example cost almost �200 – how many mums-to-be could afford to buy this just to wear for a few months?

So news that a fashion revolution is taking place on the British high street that will change the way you shop and enable you to wear designer has driven us to give our wardrobes a summer workout to make room for some new pieces.

When high street store Marks & Spencer launched 'Shwopping', an initiative that gives unwanted clothes a new lease of life by asking customers to give an unwanted item of clothing to Oxfam every time they bought something new, the scheme was supported by celebrity Joanna Lumley who is now the worldwide ambassador of the department store's Plan A eco and ethical programme.

This recycle and buy new idea is not new. Charity shops have been asking for unwanted items for years and online auction sites make it easier and cheaper to buy and sell unworn and unloved fashion.

Last year City College Norwich's Retail Skills Academy opened ego, a buy and sell boutique that enables you to sell your unwanted designer and high-end fashion and buy similar items at knock-down prices. Since the launch the shop has received many pieces that have been unwanted by some but then loved by others such as a Mulberry Bayswater handbag.

'The ethos of ego is that if you have designer or high-end fashion you no longer wear we can sell it for you in the boutique and you will get 52pc of the sale price with the other 48pc going to charity,' says head of the Retail Skills Academy Sue Dougal. 'Our charity this year is the Student New Opportunities Fund at City College Norwich. This is for students who are financially disadvantaged and is used for funding equipment they need for learning.'

Schemes like ego and Marks & Spencer's Shwopping initiative are beginning to change the way we think about buying clothes.

And they are bringing you a step closer to owning a celebrity-endorsed dress. Charity Age UK has recently launched it's Royally Hot campaign in a bid to get us all clearing out our wardrobes to donate the pieces we no longer wear to help a worthy cause and one of the donators is Sienna Miller. The actress and her sister Savannah have given the charity a few pieces from their wardrobes including the Keungzai dress. The items are going to be available from a few of the 450 Age UK charity shops in the UK – we are going to be camped out at the Plumstead Road shop just in case!

Your guide to Shwopping and charity chic

With so many Shwopping and buy and sell initiatives on the high street you may feel like having a bit of a clear out. Here's the Life Matters guide to giving your wardrobe a workout:

Try on everything in your wardrobe and create two piles: keep and throw-away. Put anything that is too big, too small or you haven't worn in over a year into the throw-away pile. Once you have finished go through the throw-away pile and sort out what items you can sell at ego and what items you can donate to a charity shop.

Identify any gaps in your wardrobe. You may be left with a lot of tops and no bottoms or vice versa. These are the items that should go on your shopping list to help you bring your whole wardrobe together.

When you go shopping make sure you stick to your shopping list and choose items from a colour palette of no more than four colours. This way you will begin to create a wardrobe full of clothes that you can mix and match to create different looks.

When making new purchases make sure they go with at least three other items in your wardrobe.

Once you have your new wardrobe have fun and experiment with different looks to see how many outfits you can make out of your clothes. Try taking a jacket from a suit and wear it with jeans or a skirt, tie a belt around the waist of a tunic dress to create a different look or turn a dress your once wore to a wedding into a summer dress by wearing it with flip flops, a big hat and a silk scarf.