THE Duchess of Cornwall, who turns 70 soon, joked about hanging on to the last few moments of her sixth decade as she was presented with an early birthday present.

Camilla's quip came when she welcomed North-East schoolchildren to her London home for a garden party to mark the milestone and celebrate a literacy competition that will see 70 books presented to 70 schools.

Books by well-known authors like Roald Dahl, JK Rowling and Ted Hughes were chosen by children across the country, and two schools which took part were invited to Clarence House, as were writers Jacqueline Wilson and comic actor David Walliams, who both made it on to the book list.

The Duchess, who is an avid reader and patron of a number of literacy charities and organisations, will celebrate her 70th birthday on July 17.

She was presented with a set of the 70 books for her five grandchildren and said: "I know most of the books backwards because I read them to my grandchildren, and we're going to have a terrible time because they're (going to be) fighting over these bookshelves - if I can plonk it somewhere in the middle they can come and borrow books."

Camilla made the group laugh when she added: "An early birthday present - I'd like to point out my birthday isn't quite yet, I'm hanging on to the last years of my sixth decade, so not quite yet."

The schoolchildren arrived in a vintage bus with Walliams acting as the conductor and the Duchess greeted them as they stepped off the red single-deck vehicle.

Walliams, whose books The Boy In The Dress and Gangsta Granny made the list of 70 books being presented to schools, said: "It's really important kids have access to books and what I like about this list is it's a fun list chosen by the kids, it's not a list we think they should read, it's a list of books they like reading and want to share with other kids."

The actor, who is an ambassador for the National Literacy Trust, said: "You never forget the book you find and read for your own pleasure, for me it was Charlie And The Chocolate Factory."

Camilla is patron or has had a close association with six organisations involved in the 70 books for schools project - the National Literacy Trust, Beanstalk, BookTrust, First Story, Roald Dahl Literary Estate and the Wicked Young Writer Awards.

The 70 schools selected to receive the books, in a specially designed mobile bookshelf, donated by publishers, have all shown they are committed to promoting reading for enjoyment, and many are in disadvantaged areas of the UK.

Pupils from Hemlington Hall Academy in Middlesbrough and Berkeley Primary School in Hounslow, west London took part in the celebrations and were joined by top children's authors Malorie Blackman, Children's Laureate Lauren Child, Cressida Cowell and Charlie Higson.

Luke Kelly, a children's author and Roald Dahl's grandson, said: "My grandfather once said in a quote, it gave him a tingling feeling down his arm to think that his hand reached into the houses of thousands of children around the world.

"And I think the idea his hand is still reaching in, and hopefully getting children to read other authors too, is I think something that would delight him and slightly amaze him."