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 Jane at the Aldwych Theatre. After several years in the West End, and a brief stint on Broadway where she appeared in Springtime for Henry in 1951, she began to appear in films. After the death of her father in 1983, Ursula Howells instigated the "Herbert Howells Society" and became a standard bearer for the promotion of his work. She financially supported the recording of his compositions and did much to encourage the publishing and promotion of church music.
tvThe Cazalets
2001
movieThe Tichborne Claimant
1999 · Lady Doughty
movieA Rather English Marriage
1998 · Mary
tvMidsomer Murders
1997 · Lady Isabel Aubrey
movieA Pinch of Snuff
1994 · Alice Andover
tvJewels
1992 · The Duchess
tvHeartbeat
1992 · Miriam Wakefield
movieTime After Time
1986 · May Swift
tvLovejoy
1986 · Olive Nettleton
tvMiss Marple: A Murder Is Announced
1985 · Miss Blacklock
movieThe Cold Room
1984 · Headmistress
tvThe Barchester Chronicles
1982 · Miss Thorne
Something in Disguise
1982 · May Browne-Lacey
tvBergerac
1981 · Elizabeth Fouchet, Laura Atherton
A Question of Guilt
1980 · Lady Uredale (voice)
movieThe Enigma
1980 · Mrs Fielding
movieGentle Folk
1980 · Mrs Menant
tvFather, Dear Father
1978 · Barbara Mossman
movieWhen the Actors Come
1978 · Barbara Karolina
tvHard Times
1977 · Mrs Gradgrind
tvBBC2 Play of the Week
1977 · Barbara Karolina
The Many Wives Of Patrick
1976
Little Fears
1974 · The Older Woman
tvFall of Eagles
1974 · Empress Maria Fyodorovna
tvPlayhouse
1974 · Mrs. Menant, Mrs. Fielding
Miss Nightingale
1974 · Aunt May
movieFather Dear Father
1973 · Barbara
Franklin's Farm
1972 · Prue
Late Night Theatre
1972 · The Older Woman
tvUpstairs, Downstairs
1971 · Duchess of Buckminster
tvCousin Bette
1971 · Adeline Hulot
tvPlay for Today
1970 · Sarah Chandler
Ryan International
1970
movieMumsy, Nanny, Sonny & Girly
1970 · Mumsy
movieCrossplot
1969 · Maggi Thwaites
tvITV Saturday Night Theatre
1969 · Mrs. Clissold
tvFather, Dear Father
1968 · Barbara
tvOoh La La!
1968 · Mme Pontagnac
movieAssignment K
1968 · Estelle
movieTorture Garden
1967 · Miss Maxine Chambers (segment 3 "Mr. Steinway")
tvMan in a Suitcase
1967
tvHalf Hour Story
1967 · Peggy
tvAll Gas and Gaiters
1967 · Mrs Buckley
tvThe Informer
1966 · Lady Tregunter
tvThirty-Minute Theatre
1965 · Ellen
The Wednesday Thriller
1965 · Hilda
Six Shades of Black
1965 · Netta Bartholomew
movieDr. Terror's House of Horrors
1965 · Mrs. Deirdre Biddulph (segment 1 "Werewolf")
movieA Choice of Coward: Present Laughter
1964 · Liz Essendine
tvA Choice of Coward
1964 · Liz Essendine
movie80,000 Suspects
1963 · Joanna Duten
tvThe Human Jungle
1963 · Julia Gray
movieThe Madhouse on Castle Street
1963 · Martha Tompkins
movieThe Sicilians
1963 · Mme. Perrault
movieTwo Letter Alibi
1962 · Louise
Drama 61-67
1961 · Claire
Sunday-Night Play
1960 · , Janet Ormund
Theatre '70
1960 · Jessy Tomson
tvNo Hiding Place
1959
tvInterpol Calling
1959 · Miki
movieNow Let Him Go
1957 · Nurse Judith
movieAccount Rendered
1957 · Lucille Ainsworth
movieWest of Suez
1957 · Eileen
tvArmchair Theatre
1956 · Margaret, Violet Green, Nurse Judith, Prue
movieThe Long Arm
1956 · Mrs. Elliot / Mrs. Gilson
movieKeep It Clean
1956 · Pat Anstey
movieThey Can't Hang Me
1955 · Antonia Pitt
tvLilli Palmer Theatre
1955 · Mary
movieTrack the Man Down
1955 · Mary Dennis
movieThe Constant Husband
1955 · Ann
movieThe Gilded Cage
1955 · Brenda Lucas
tvSherlock Holmes
1954
movieThe Weak and the Wicked
1954 · Pam Vickers
movieThe Blakes Slept Here
1953 · Emily
movieThe Oracle
1953 · Peggy
movieNumber Three
1953 · Maureen Dartington
movieI Believe in You
1952 · Hon. Ursula
movieThe Cocktail Party
1952
movieFlesh and Blood
1951 · Harriet Marshall
tvSunday Night Theatre
1950 · Mary Winsloe, Maureen Dartington