Barbara Margaret Trimble, who also wrote under the pseudonyms Margaret Blake and Barbara Gilmour, was a British author active between 1967 and 1991. She produced over 20 novels across the crime, thriller, and romance genres.

Born Barbara Margaret Gill in Holyhead, Wales, her heritage included both Irish and Welsh ancestry. Trimble's writing career saw her nominated for the Edgar Award for Best Novel on two occasions: in 1985 for "The Twelfth Juror" and again in 1988 for "Nursery Crimes." She passed away in 1995.

Her literary output was diverse, with works published under three distinct pen names. As Margaret Blake, she released titles such as "Stranger at the Door" and "Courier to Danger." Under the name B. M. Gill, she penned "Target Westminster," "Death Drop," and the Inspector Maybridge series, which included "Victims" and "The Fifth Rapunzel." Her publications as Barbara Gilmour featured novels like "You Can't Stay Here" and "Threads of Fate."