DIGGING DEEP BBC2, 8.30pm

TIM MARLOW ON HOLBEIN Five, 7.15pm

"PRIME-TIME slot, BBC2, Tuesday nights. What to do, what to do, what to do . . . Got it! Picture this: a garden makeover show but instead of Charlie Dimmock we use Trinny and Susannah."

"They've defected to ITV to do that fashion therapy thing."

"Dammit, so they have. But wait: we could use that idea. Instead of fashion therapy we could have 'garden therapy'."

"I like it! We take two presenters and get them to assess the state of someone's life from the state of their garden."

"And by helping improve the garden, they help improve their lives."

"Exactly! It can't fail!"

I'd like to imagine that's how Digging Deep came about; well, I reckon it had to be something like that because this is television at its most derivative.

Digging Deep works like this: Andre Smith and Amanda Brooks, garden designers who glory in the alternative title of "horticultural therapists", go into a garden and deduce stuff from it about the owners' lives. They then give it a facelift, Changing Rooms-style.

Theatrical Amanda is the personality - I doubt so many "dahlings" have ever been uttered in so short a time - while Andre is the quieter one.

I was rather under the impression that as they were "digging deep", Andre and Amanda would have some important insights to share with us, but perhaps I'd misunderstood.

We met them en route to their first job, the garden of a house near Wolverhampton. Once there, came the "diagnosis". It was overgrown and contained lots of stuff, including two sheds and an abandoned, rusting bike.

"There's a sense of abandonment and rusting, " said Andre. His eye then alighted on some fairly pristine-looking paving slabs to one side. "The slabbing looks new, doesn't it, as if something's started. If you start something and it comes to a stop, does that mean something's happened?"

As it turned out, the house belonged to a very charming couple called Mike and Vicky. Looking after the garden, understandably, had fallen to the bottom of their list of priorities when Vicky was diagnosed with breast cancer two and a half years earlier. After a course of treatment, Vicky had recovered - and in two weeks would have her last reconstructive operation. The couple wanted a new garden so they could move on.

Back in the garden, Andre was excited about a new gazebo: "Do you knowwhat I want? Fabulous roses dripping all around them! Sanctuary. Healing. Peace."

Amanda: "The vision is so soft and gorgeous!" (Points to her own eyes. ) "My eyes are now suddenly thrilled!"

The finished garden was, of course, very nice. They filled it with colour and scent and herbs, and it was touching to see Vicky and Mike so overwhelmed by it. They're good garden designers, Andre and Amanda, and Vicky and Mike needed a helping hand, but "therapists"? That's stretching it.

It was our imaginations that were being stretched over on Five. Rarely in these days of graphic TV reconstructions are viewers allowed to fill in anything with their imaginations. So Tim Marlow on Holbein, which featured only Tim Marlow, some Holbeins and some Tudor music, was a refreshing change.

Art expert Tim took us round the Tate Britain's new exhibition of Holbein's work, the biggest in the UK for 50 years. It sought, he said, not only to emphasise Holbein's place as the "father figure of British art" but "to establish him as one of the greatest painters of the human face who ever wielded a brush".

There was no arguing with that: Holbein's Tudor courtiers are so full of humanity, you want to stop for a chat.

His iconic image of Henry VIII, meanwhile, defined the era. By the end, we understood why Holbein was so influential - and all without the help of extras in comedy beards.