Taking place under the theme of 'Inspiration', the envelopes are currently on sale on the online auction site eBay until 22 March to help raise money for the National Literacy Trust.

Figures taking place in the campaign include Dame Judi Dench, children's author Rod Campbell, comedian Jo Brand, singer Dame Shirley Bassey, Olympian Sally Gunnell OBE and Dame Helen Mirren,

Uri Geller will also take part and has produced a mythical design that is claimed to deter bad luck.

Pitney Bowes EMEA director of marketing and sales operations Bart Leonard said the manufactuer shares values of effective communication with the National Literacy Trust.

He added: "All funds from Pushing the Envelope help the National Literacy Trust transform lives through literacy and offer those in the UK with poor skills the chance to gain greater confidence, employability and opportunities.

"Over the years, the Pitney Bowes 'Pushing the Envelope' project has raised over £80,000 for the National Literacy Trust, and we aim to make this year our most successful to date."