2 sophisticated dramas from BBC

Cable network BBC America once again shows up its broadcast brethren with two new, sophisticated, genre-bending dramas from across the pond:

Mistresses

and the highly anticipated

Life on Mars

sequel,

Ashes to Ashes

.

Mistresses, which premieres tomorrow at 8 p.m., is a steamy ensemble drama about four London women on the cusp of middle age who help one another navigate their complicated and sometimes downright dangerous sex lives.

It's Sex and the City London-style, but with a darker edge, and more brains and gravitas.

In the series opener, Katie, a successful doctor - played by the wondrously sultry Sarah Parish (Viva Blackpool) - has just lost the love of her life to cancer. Trouble is, John was married to another woman. More scandalous still, Katie, who was his doctor, helped him end his life.

The conflicted Katie begins to panic when John's son suspects the affair, then falls desperately in love with her.

Complicated and perverse enough? Multiply that by four and you get an idea of the conflict, sexuality, despair and comedy woven throughout the series.

Katie's friends have equally tangled lives. Trudi (Sharon Small from The Inspector Lynley Mysteries) is a 9/11 widow who hasn't been able to accept her husband's death.

Nip/Tuck's Orla Brady plays Siobhan, a lawyer stunned when her perfect marriage begins to fall apart.

The group's youngest, Jessica (Shelley Conn), is a self-described man-hungry nympho who finds herself drawn to a lesbian. All of this happens in the first two episodes. Strap in for a fun, twisty ride.

Ashes to Ashes, which premieres March 7 at 9 p.m., is the superior show. A brilliantly written postmodern time-travel cop show, it tops its prequel, Life on Mars, which had a successful run in Britain and inspired the ABC remake.

Keeley Hawes (MI-5) stars as Alex Drake, an ambitious police profiler who has become fascinated with strange reports left by old-time cop Sam Tyler. Tyler is the protagonist in Mars, who was transported from 2006 to 1973.

Next thing she knows, Alex is shot in the head by a particularly nasty villain and wakes up wearing a miniskirt, garter belt, stockings and very nasty stilettos. It's 1981. Diana is about to wed Prince Charles, and Alex's parents are about to be murdered.

Alex finds herself with the same squad of cops as Sam, including the boorish, sexist, stone-age caveman Gene Hunt (Philip Glenister), whom she enlists to help her solve the mystery of her parents' death. Ashes, which is filled with Lynchian flights of surreal fancy, amps up the mystery and wonderfully develops Alex and Gene's frisson-laden, Hepburn 'n' Tracy relationship, full of bile and vinegar - and lust.

TV is rarely as good as this.