Howells was born in London, the daughter of composer Herbert Howells, and was educated at St Paul's Girls' School, where her father worked as Director of Music. She made her first stage appearance at Dundee in 1939, in John Drinkwater's Bird in Hand, then moved to Oxford in 1942 and three years later made her London debut at the Embassy Theatre, Swiss Cottage. In 1947 she appeared in the comedy
Assignment K
⭐ 6Dr. Terror's House of Horrors
⭐ 6.4Mumsy, Nanny, Sonny & Girly
⭐ 6.1Time After Time
⭐ 0Now Let Him Go
⭐ 0Account Rendered
⭐ 5.8Crossplot
⭐ 5.5Father Dear Father
⭐ 4.8Track the Man Down
⭐ 5.8The Gilded Cage
⭐ 5.2The Cocktail Party
⭐ 080,000 Suspects
⭐ 6.5Miss Nightingale
⭐ 0The Long Arm
⭐ 7West of Suez
⭐ 0Torture Garden
⭐ 6Gentle Folk
⭐ 0Two Letter Alibi
⭐ 5Franklin's Farm
⭐ 0Little Fears
⭐ 0The Sicilians
⭐ 5.5A Rather English Marriage
⭐ 5.7They Can't Hang Me
⭐ 6Flesh and Blood
⭐ 0The Tichborne Claimant
⭐ 8A Pinch of Snuff
⭐ 0The Oracle
⭐ 5The Constant Husband
⭐ 6.9The Weak and the Wicked
⭐ 5.9Keep It Clean
⭐ 4.5The Madhouse on Castle Street
⭐ 0The Cold Room
⭐ 3.3I Believe in You
⭐ 6.1The Enigma
⭐ 0When the Actors Come
⭐ 0The Blakes Slept Here
⭐ 0⭐ 7.5⭐ 6.4⭐ 7⭐ 7.3⭐ 7.1⭐ 6.7⭐ 5⭐ 6.7⭐ 3.7⭐ 6.8⭐ 7⭐ 0⭐ 5⭐ 0⭐ 5⭐ 8⭐ 8.2⭐ 6.1⭐ 0⭐ 7.64⭐ 7.2⭐ 3.5⭐ 6⭐ 6.4⭐ 8⭐ 5⭐ 0⭐ 5.8⭐ 7⭐ 3.5