Lancelot “Lance” Fortescue is a character in A Pocket Full of Rye. He is the younger son and engaging black sheep of the Fortescue family. He lived in East Africa for a time, due to a long-standing estrangement between him and his father. The estrangement was due to a forged cheque, which had been paid into Lance's account.
Mr Rex Fortescue's sudden change of heart regarding his younger son is seen by the elder as further evidence of mental imbalance. Lance arrives at the family home expecting fatted calf and is instead greeted with the news that his father is dead, murdered. Since Lance was still in France at the time of Rex Fortescue's death, he is not considered a suspect.
Lance has recently made what his father considers a 'good' marriage to Pat, the impoverished but aristocratic daughter of an Irish peer, with a history of choosing attractive rogues as husbands. Lance is devoted to her. He makes up with his family and faces the grim prospect of life 'in the City' entirely for her sake.
Lance has a "dark lean face", and is very attractive to women. At the office of Consolidated Investments Trust, he creates a flicker of excitement in the typists' room when he comes in.
After their father's death, Lance's older brother, Percival, tells him that they would not be able to work together, and that they should dissolve the partnership by dividing the holdings. They argue, and Lance tells Percival to keep the safe investments and give him the speculative ones, including the Blackbird Mine.
The summer before the events of the novel, Lance had met Gladys at a holiday camp, and had flattered her and made love to her. He told her that his name was Albert Evans, and that he had been swindled by Rex Fortescue. He convinced her to take a post at Yewtree Lodge, Rex's home, when one became available. He also told her that he had a friend working in a factory that made "truth drugs", which would make a person tell the truth.
Lance arranged a date with Gladys, when she was to put the "truth drug", in Rex's marmalade, and put rye in the pocket of his jacket. He was to call on Rex at his office, where Rex would admit what he had done in front of witnesses. In reality, the "truth drug" was taxine, and he was in Paris at the time of Rex's death, giving him an alibi.
When Lance arrived at Yewtree Lodge, he first went to the side door, and beckoned Gladys to come out to him. When she did, he strangled her, and clipped a clothes peg on her nose. He then went inside, and joined the family for tea.
After tea, he came back to the drawing room, where Adele was alone, and slipped cyanide into her tea cup.
The novel closes with Miss Marple receiving a letter from Gladys, explaining how she had put the "truth drug" in the marmalade in order to help "Albert". A photograph of Gladys and "Albert" is enclosed, providing the proof that is needed to bring Lance to justice.
In the BBC 1985 adaptation of the novel which formed part of the Miss Marple series, the part of Lance is played by Peter Davison. Here he dies at the end of the episode in a vehicle collision while trying to get away. Before this, he confessed his crimes to Pat and tells her that he did it all for her.
In the ITV 2008 adaptation of the novel (Episode 1, Season 4 of Agatha Christie's Marple), the part of Lance is played by Rupert Graves. Here, as in the original, Miss Marple leaves Yew Tree Lodge towards the end of the show with Lance thinking perhaps that he has gotten away with it. When Miss Marple returns to St. Mary Mead, she opens a letter from Gladys with the photograph which would be conclusive proof of his crime.