Every year since 2013, the poet, broadcaster and author Lemn Sissay has arranged a Christmas dinner for people aged 18-25 who have left the care system and have no one with whom to have Christmas dinner. No one to give presents or receive them. No-one on the other end of the cracker.

This is not a charity. It isn’t even an organisation. It’s a project Lemn undertook because he understands how it feels – at 18 he was released from a children’s home and given an empty flat in Wigan, with no one in the world who had known him for longer than a year.

Lemn Sissay’s Social Enterprise is a four-part series for BBC Radio 4, considering what these dinners have taught him about charity, social enterprise, and people, through stand-up, interview and poetry.

This week, he explores the idea of shelter in all its forms – with the help of Polly Neate, the Chief Executive of the charity Shelter, and comedy writer Sarah Morgan.

This week he explores the idea of food – with the help of Nick Cole, the UK project director for Operation Christmas Child, and comedian Jason Cook.

This week he explores the idea of time – with the help of Jill Mortimer from Age UK, Anna Chojnicka from the Global Entrepreneurship Network, and comedian and podcaster Deborah Frances-White.