As the wet sand squelched between his toes, the young boy's face lit up with sheer joy.

It was yet another "first" he had experienced while living with foster carers, and he was loving every minute of it.

"He had never been to the beach before and his face was a picture, it was a delight to see," remembered foster carer Sandra Young.

It is moments like this which make her fostering role so worthwhile, but she is under no illusion of how hard it can be.

The first child in her care, more than two years ago, was "extremely challenging".

With three children of her own and her experience as a paediatric nurse at Colchester General Hospital, Sandra says her life had always been "steeped in children".

"But until you start fostering, you don't appreciate the damage and trauma some of these children have gone through," she said.

Sandra and her husband, Chris, of St John's, Colchester, feel they are lucky, very lucky. They have a happy, loving home and three "fantastic" children - Hannah, 13, Jonathan, 11, and Abigail, eight.

What makes them stand apart is they felt they wanted to share their good life with children in need of short-term fostering.

Problem is, there are not enough like them. Figures released by charity Fostering Network for Foster Care Fortnight, which began on Monday, reveal more than 4,200 new foster carers are needed in England.

It is not a role to be taken lightly.

Some foster children have had such traumatic childhoods that conventional parenting skills just don't work. They have never been really cared for, so they don't really care about anything. Offers of rewards or treats for good behaviour, for example, go straight over their heads.

"You have to learn different ways of coping and be more creative," said Sandra.

Sandra has nothing but praise for how her children have coped with having foster children sharing their home. They have been keen on the idea from the start and have adapted well, despite seeing a very different side to life than the stable family unit they enjoy.

"They will become very good parents," said Sandra, 44. "They even make suggestions now about certain situations."

For Sandra, the qualities needed for fostering are patience, a sense of humour and being non-judgmental.

"You also need to be very adaptable, flexible and creative," she said, laughing. "Yes, you definitely need to think outside of the box."

The hardest part for Sandra is when the children leave.

"Even the most challenging children leave a hole in their family life," she added.

"It is because you give your all and devote yourself to them."

The reward of knowing they have thrived, after finally experiencing life in a loving home, is one that will stay with them, and the foster carers, forever.

For more information call Freephone 0800 801530 or visit essex.gov.uk/adoptionandfostering