"At the river's source, in Lechlade, it was actually quite nice. But by the time you get into central London, it stank..."

In this week’s Radio Times, comedian David Walliams relives his epic swim down the Thames to raise money for Sport Relief: from saving drowning dogs to swallowing passing parasites, and sustaining spinal injury to suffering Miranda Hart’s microwaved porridge.

Also this week:

Springwatch presenter Kate Humble tells us why she’s staked her future on a rundown farm

Find out how South Shields civil servant Sarah Millican conquered the world of comedy

Writer Paula Milne explains how she’s mined her past for White Heat, a new drama that spans the 60s to today

What links Eleanor of Aquitaine and the present Queen?

We ask Noel Gallagher “the best question I’ve been asked in 20 years in the music business”. But what’s his answer?

Former Time Lord David Tennant gives us his take on Tree Fu Tom, a new series that aims to get kids off the sofa

Meet the new boy racer on the starting grid – F1 star Lewis Hamilton’s brother, Nic

Did you win? Barry Norman names his 101st favourite film from your suggestions

Dominic West admits he Googles himself and watches his own shows

Next week in RT… It’s the MasterChef final – who’s the toughest?... Manchester’s finest, Scott & Bailey, on fighting crime and prejudice…and 24 star Kiefer Sutherland returns... On sale Tuesday 6 March.