QI (BBC, 10pm)

FOR the past 13 years, Stephen Fry, the actor, writer, director and presenter, made the fiendishly difficult panel quiz show appealing with the assistance of comedy stooge Alan Davies, and a bunch of special guests.

Now, his ultra-big chair is being filled – well some of it anyway – by diminutive Sandi Toksvig, who has presented BBC Radio 4's The News quiz for nearly a decade and has found her feet quickly it appears. Perhaps that has something to do with her taking part as a panellist 16 times.

Producer John Lloyd was the man who persuaded Fry to take on the brain-bashing quiz in the first place and, according to Davies, tricked him into becoming the butt of most of Fry's jokes. When QI went down well, there was little surprise when a second series was given the green light. Suddenly the concept of actually making 26 series – one for each letter of the alphabet – went from being a pipe dream to a reality.

Fry was still very much in demand last year, but when it was announced that he was going to step down, there was perhaps little surprise. He was half way through the series' planned run, so not a bad time to pursue other ventures.

Toksvig still has work to do to show she can generate the same magic as the much missed question-master, or whether the audience take to her. After all, when Never Mind the Buzzcocks dispensed with its guest hosts after several series and Rhod Gilbert (who made two QI appearances) became the regular frontman, it was axed soon after.

That's the problem with hosts stepping into a show after more than a decade on the box. No matter how skilled they are, audiences fear change, and a Fry-free QI might haemorrhage viewers.

For the first of the new series, Toksvig and Davies will be joined by Cariad Lloyd, a veteran of the Edinburgh Fringe who has cropped up in a couple of previous QI episodes, as well as Inside No 9, and Siblings.

And given their appearances on assorted quiz shows, Romesh Ranganathan and Phill Jupitus perhaps need no introduction. They will all answer questions on subjects associated with the letter N.

Since the enquiries are impossible to answer, points are awarded for being interesting rather than correct.

Stand Up to Cancer (C4, 7pm)

IT'S that time of year again when the main TV companies pull out all the stops for their chosen charities, and for the latest, Channel 4 have a feast of entertainment lined up. The aim, as you'll have gathered, is to persuade us to part with our cash, which will go towards finding a cure for cancer. Davina McCall, Alan Carr and Adam Hills guide us through the proceedings, and some famous faces will be giving their verdict on small screen gems in Celebrity Gogglebox. Hills returns for a special edition of The Last Leg, and a galaxy of stars, including Jamie Dornan, Michael Buble, Britney Spears, Noel Gallagher, Olivia Colman, David Tennant, Jon Hamm and Eva Longoria have done their bit to ensure we keep that cash flooding in. There will also be an appearance by Steve Coogan as celebrities take on a series of challenges. Jose Mourinho and John Bishop will trade dad jokes while Rick Astley will be taking on Meat Loaf at Buckaroo.

The Graham Norton Show (BBC1, 10.35pm)

HOLLYWOOD great Tom Cruise, currently starring in Jack Reacher: Never Go Back, joins Graham along with his co-star Cobie Smulders. Jude Law discusses his appearance in new television series The Young Pope, while comedian and actress Catherine Tate also takes up a place on the sofa. Plus, supergroup Kings of Leon perform their new single, Waste a Moment. If there's time, Graham will also subject more audience members to the dreaded red chair - so their stories had better be good.

Viv Hardwick