'I like being Jack one day, and the beanstalk the next." Frederick, a confident 10-year-old, laughs, a big beam spread across his cherubic face. "If there are difficult words, Juliette helps me."

"It's changed my life," she says simply. Juliette Premdas is a well-dressed retired woman with a soft northern accent, who has a grown-up child of her own. She signed up to be part of the Volunteer Reading Help (VRH) scheme a year ago and now couldn't do without it. Twice a week, she goes into Ecclesbourne primary school in north London to see her three friends, Frederick, Sara and Candace.

This year, VRH celebrates 30 years of training volunteers and sending them into primary schools to help children with their reading and communicating skills. Given this week's survey from the government's basic skills agency about children's poor language development on entry to education - partly because pressed modern parents don't have time to read stories to their children - VRH's service has never been more needed.

"I don't think you could do this sort of volunteering unless you really like children," says Juliette. "It's not just about helping out at the school, or feeling like you've earned your Brownie points because you've done something for the community.

"It's so rewarding having real relationships with my three. I really miss seeing the children during the holidays, and I love coming to see them in their school plays when often their parents are too busy."

Juliette saw on the national TV news that schools needed volunteers to help. "And then I saw a leaflet in the library. What surprised me was that it has been going for so long and operates all over the country and yet I had never heard of it."

Susan Belgrave, MBE is president and founded VRH. Now in her 70s and still raising funds for her charity, she recently completed a sponsored 500-mile ride across Turkmenistan. What began with six friends helping a score of children to read has become a force of almost 3,000 volunteers of all ages, both male and female, helping 8,000 primary school children all over the country. The original principles of the scheme haven't changed. Volunteers still have to commit themselves for a full school year for at least an hour a week; but there are no qualifications necessary other than patience, understanding and a sense of fun.

"I can't do a full-time job," Juliette explains. "so this suits me. I look forward to it twice a week, three hours in all, and it's only during term time. It's not a great sacrifice."

Teachers pick out the children who need help. They may be struggling to keep up with their class mates because they are younger than the rest or they may be new to this country or learning English as their second language. Often, there is enough pressure in young children's lives, from having to help care for their younger siblings, to both parents being too tired after work to play or read. In such cases, as the skills agency reports, these children's ability to communicate does not develop. The child can end up disappearing into the back of the class.

Time with their volunteer, though, is time away, when they get all the attention and focus. This can make a tremendous difference to many children's school lives. It can stop truanting and, as many teachers testify, can encourage disruptive children to become a part of the class again. Teachers have reported that 77% of the children supported by VRH demonstrate "an outstanding improvement" in reading skills and 82% in confidence.

School can often seem like a place where, as a child, you do not get much individual choice; teachers tell the whole class what to do. So the children need not feel singled out as less able than their classmates (Jamie Oliver said the kids used to sing "Special needs" at him when it was time for his extra-learning session). Here, there is no stigma attached; these sessions are not compulsory and it is not just about reading. When told that Juliette would be coming to see her twice a week, one little girl asked in amazement, "What, you mean you're coming just to see me and read books or play games that I want to do?"

"Sometimes we play Boggle [a word game rather like a scaled-down version of Scrabble], but my favourite game is Sneaky Sharks," giggles Frederick, throwing Juliette a look. She laughs back, showing the obvious rapport that has developed between them. "A lot of the children like that game," she explains. "It's sort of Snap with sealife."

Frederick explains: "My mum went to take me to the library in Hackney, but it has closed down where I live. So Juliette brings new books or ones about things I like - like football. I like the quiet of being alone without all the others in the class - and now I can help my little sister read."

The feeling of being important obviously rubs off; children not picked out for the scheme frequently request it. They love the attention. And stories often contain moral tales that can help the them solve their own personal relationships.

It can take a couple of months to match the volunteer to the school, to schedule the day's training and an interview with an area supervisor who makes sure all your credentials are sound. "I wasn't nervous that first morning I did it but I wasn't feeling terrific," admitted Juliet. "But I thought, 'I can't let this poor child down.' I had promised I would be there. There had been a mix-up and I hadn't got the background notes on the children and Sara [9], a Turkish girl who lives with her grandmother, went for the most babyish book available, but it's not for us to say anything. We encourage them to make different choices and to talk about what they choose and why they like or don't like a book. She could hardly speak English and now, almost a year later, she's reading Winnie the Pooh in the original, and loving it."

Many of the children do not even have any books in their homes - English or otherwise - and this obviously makes it harder for them to cope at school. Often children are sent to bed with the television or a video in their bedrooms to keep them occupied, instead of having their parents reading them a bedtime story.

"VRH has never been needed so much," said Cleo Whittaker, Juliette's area co-ordinator who supplies her with the games, support and reading materials. "And it's really a win-win situation. The kids love it and thrive, but then so do the volunteers."

· Volunteer Reading Help is on 0845 601 4008 or at www.timebank.org.uk/readability. Donations to VRH (a registered charity) can be made by calling 0870 7744300.

Tomorrow is World Book Day; for further details, see www.worldbookday.com.