Betty Mabel Lilian Uelmen (née Williams; 11 January 1919–6 September 1974) was a British journalist, screenwriter and pulp fiction writer who used the pen names Dail Ambler and Danny Spade. She was also known professionally as both Betty Williams and Betty Uelmen.
She was born in Aldershot in Hampshire and worked as a Fleet Street journalist and correspondent before settling on a career in fiction writing. By 1950, she was publishing at least one novel a month under the Danny Spade name for pulp paperback publisher Scion Ltd; she later wrote for Milestone Publications. Her writing style and content was somewhat influenced by Mickey Spillane. After the boom in pulp fiction in the United Kingdom ended in the mid-1950s, she turned to screenwriting under the Dail Ambler name. She later lapsed into semi-retirement in Surrey, where she died at the age of 55.
- The Dame Plays Rough (1950) by Danny Spade
- Waterfront Rat (1951) by Danny Spade
- Calling Mr. Spade (1952) by Danny Spade
- The Lady Says When (1952) by Dail Ambler
- Honey, You Slay Me (1953) by Danny Spade
- White Curves and Black Coffee (1953) by Danny Spade
- The Virgin Collector (1971) by Dail Ambler
- Three Men for the Job (1975) by Dail Ambler (posthumous)
- Beat Girl (1960), directed by Edmond T. Gréville
- Take Me Over (1963), directed by Robert Lynn
- Night after Night after Night (1969), directed by Lindsay Shonteff
- two scripts for Armchair Theatre
- The Pillars of Midnight (1958)
- Murder in Slow Motion (1958)
- one episode for Harpers West One (1961)
- "Intended Dividends" (PDF). London Gazette. January 10, 1974. p. 428.
- Server, Lee (2014). Encyclopedia of Pulp Fiction Writers. p. 11. ISBN 1438109121.
- Grave of Dail Ambler - Find a Grave
- "Dail Ambler". British Film Institute.
- Stafford, David; Stafford, Caroline (2015). Big Time: The Life of Adam Faith. p. 46. ISBN 1783233958.