Such is the success of the profile - which also contains each child's photograph, as well as examples of their work and comments from parents - that schools around the country have been writing to the borough seeking to adopt the same system.
It is used in all primaries, day nurseries and social services departments, and is an open document, accessible to parents and children and to the services that need the information. Indications are that parents love it. Teachers find it time-consuming - it takes big chunks of time to complete - but useful.
Unlike baseline assessment, the profile cannot be used to compare children with one another. It is subjective and descriptive, and not capable of standardisation. It thus has a different purpose to testing. It is valued because it looks at the whole child; his or her personal development, family circumstances, as well academic progress in detail over two years. Deryn Welbourne, headteacher of Holy Trinity School, favours it: "It's an on-going record so you can see the progression."
She and the teachers at Holy Trinity say it is a useful way of educating parents about the curriculum and their children's skills. It shows them, for example, what a slow business learning to read and write is by recording the small, but key developments on the road to literacy.
Developed by a group representing all the services that deal with the under- fives, from teachers to health visitors to day nursery staff, the profile is designed to ensure that children entering school at four are accompanied by decent records.
Teachers are required to observe children under various headings - covering emotional, social and physical development, communication, language and literacy, mathematical and scientific development - and record comments. Thus Abdullah (not his real name) received the following entry in October last year, early on in his first term. "He is still very unsure of his new environment. It was helpful today that mum stayed and engaged in some activities with him. "
By the following March he had adjusted well and made some friends, says the teacher. A year later, he is playing with a range of children and is chatty and confident. More important still, he is not afraid of new adults.
The teacher records that on the mathematics front, Abdullah is counting up to five, that he is really interested in the computer and fascinated with painting.
As the guidelines for teachers put it: "The profile provides positive and relevant information about the child's achievements in a setting where shehe is well known and confident.
"This is particularly important as schools need to make formal assessments of the progress that children make in the national curriculum: superficial judgments can disadvantage your children."
Teachers complete the profiles on a timetable. Vicky Godbeer, the reception class teacher at Holy Trinity, aims to make written observations on four children a week. The idea is to talk to the children about their learning and get them to write and draw pictures in their profiles to show what they can do.
Kensington and Chelsea sets great store by involving parents. Information about the profiles has been translated into a range of languages, including Arabic, Gujarati, French and Bengali and mothers and fathers are invited to record their own observations on the record - although the only negative feedback has been from parents who feel put on the spot because they cannot write and therefore cannot contribute.
Angie Phillips, the borough's chief inspector, says one of the profile's great advantages is that it enables schools to use it as they want. "There is flexibility but there's a framework too," she says.