Sandi Toksvig is joined by Aisling Bea, Urzila Carlson, Romesh Ranganathan and Alan Davies for an upside-down episode.

Sandi Toksvig, Nabil Abdulrashid, Bill Bailey, Victoria Coren Mitchell and Alan Davies are all in it together for this United episode.

Join Sandi Toksvig for a thoroughly Unsavoury episode of QI, with Gyles Brandreth, Judi Love, Kiri Pritchard-McLean and Alan Davies.

Sandi Toksvig puts the UK-US special relationship under the microscope with Kemah Bob, Alex Edelman, David Mitchell and Alan Davies.

Sandi Toksvig presents an ultra-interesting episode of QI with Jordan Gray, Jason Manford, Sara Pascoe and Alan Davies.

Sandi Toksvig dusts off her tinfoil hat for a look at ufology with Cally Beaton, Nish Kumar, Tom Ward and Alan Davies.

Sandi Toksvig, Rhod Gilbert, Lara Ricote, Ahir Shah and Alan Davies look at some animals beginning with 'U'.

Sandi Toksvig looks at a range of unrelated 'U' topics with Tom Allen, Chris McCausland, Lou Sanders and Alan Davies.

Sandi Toksvig hosts an 'upsadaisy' episode of QI and is joined by Justin Moorhouse, Emmanuel Sonubi, Holly Walsh and Alan Davies.

Sandi Toksvig is joined by Maisie Adam, Daliso Chaponda, Jack Dee and Alan Davies for a look at some underthings.

Sandi Toksvig goes to university with Guz Khan, Joe Lycett, Morgana Robinson and Alan Davies.

Sandi Toksvig takes a look at upbringing with Sally Phillips, Josh Pugh, Aaron Simmonds and Alan Davies.

Sandi is joined by Zoe Lyons, Dan Tiernan, Josh Widdicombe and Alan Davies for an underground and underwater episode of QI.

Sandi Toksvig is joined by Bridget Christie, Rosie Jones, Cariad Lloyd and Alan Davies to find out about ulex and other obscure U words.

A selection of the best moments from series U, with Sandi Toksvig, Alan Davies and their guests.

More of the best moments from the U series of QI, hosted by Sandi Toksvig with Alan Davies and their guests.