According to Official Guinness Records,
The longest live broadcast for a charitable event lasted 11 days 11 hr 11 min and was organized by Penny Appeal (UK), at British Muslim TV Studios in Wakefield, West Yorkshire, UK, from 2 to 14 July 2015. UK-based humanitarian charity Penny Appeal was launched in 2009 and now works in thirty countries worldwide
For a complete list of 2015 records, please visit 2015 Guinness Records in United Kingdom.