The Reading Agency is to receive a £1m donation from the Paul Hamlyn Foundation.
The gift will support the expansion of the charity's work with young people and libraries, with a new "Reading Activists Challenge" aiming to create 95,000 young volunteers across the country.
The Paul Hamlyn Foundation makes grants to organisations which help individuals to realise their potential and has focused particularly on disadvantaged children and young people. It is marking its 25th anniversary in 2012-2013 with a series of five large gifts on top of its usual grants, and the £1m donation to TRA is the final one of those gifts.
TRA's Reading Activists are young people aged 11-19 who build their own reading skills while acting as reading mentors to younger children. A key part of the new Reading Activists Challenge will consist of volunteering on another TRA programme, the Summer Reading Challenge aimed at children aged 4-11.
TRA director Miranda McKearney said: "The Paul Hamlyn Foundation's recognition of the charity's work through this astoundingly generous anniversary gift is deeply heartening. It will help us work with community partners like libraries to inspire thousands more young people to become active citizens and enthusiastic readers."
The gift was announced at a reception at number 11 Downing Street this evening (8th July) to mark the launch of the 2013 Summer Reading Challenge, which has a "Creepy House" theme.
Children's laureate Malorie Blackman, and authors Cressida Cowell, Liz Pichon and Chris Riddell attended the event, alongside librarians, publishers, MPS and local councillors.