Hubert Gregg's love song to his home city "Maybe It's Because I'm a Londoner" will never be forgotten, and his full and varied career embraced acting, directing, writing plays and novels, and presenting the very popular BBC Radio 2 series Thanks for the Memory.

Hubert Robert Harry Gregg, broadcaster, actor, songwriter and theatre director: born London 19 July 1914; MBE 2002; married 1944 Zoe Gail (one daughter; marriage dissolved 1950), 1956 Pat Kirkwood (marriage dissolved 1979), 1980 Carmel Lytton (one son, one daughter); died Eastbourne, East Sussex 29 March 2004.

Hubert Gregg's love song to his home city "Maybe It's Because I'm a Londoner" will never be forgotten, and his full and varied career embraced acting, directing, writing plays and novels, and presenting the very popular BBC Radio 2 series Thanks for the Memory.

Gregg was born in London in 1914. His father was wounded in the Somme and, with no income, sold toys in the street, but four miles away from his home so as not to shame his family. The boy Hubert won a scholarship to a public school, St Dunstan's College, in Catford, but his parents couldn't send him to university. Instead, he enrolled at the Webber-Douglas School of Singing and Dramatic Art and, between 1933 and 1936, he played a multitude of roles for the Birmingham Repertory Company, the Old Vic and the Open Air Theatre in Regent's Park.

In 1933 Gregg made his first broadcast as part of the cast of Cabbages and Kings with the Birmingham Rep. In 1937 he played the leading role in French Without Tears, first on Broadway and then in the West End during 1938/39.

During the Second World War, he served as an officer with the 60th Rifles and in 1942 was seconded to broadcast in German to the German forces. "I must have been good at it," he reflected, "because Goebbels accused me of being a traitor." In the same year, he appeared with Noël Coward, John Mills and Michael Wilding in David Lean's flag-waving film about a torpedoed destroyer, In Which We Serve.

He wrote "I'm Going to Get Lit Up (When the Lights Go Up Again in London)" in 1940 but the musical-comedy star Hermione Gingold refused to sing it. "She said quite correctly that we couldn't sing about getting lit up when we didn't know who was going to win," said Gregg. The song was launched in 1943, when victory was on the horizon, and was recorded by Alan Breeze with Billy Cotton and his Band. Winston Churchill subsequently told Gregg that the song was used as a broadcast signal to the Resistance that the invasion of Europe was under way. Nancy Astor was horrified by the song, thinking it might incite drunkenness.

In 1944 Gregg wrote "Maybe It's Because I'm a Londoner". He said, "It took me 20 minutes to write it before supper one night. It's only got 16 bars, but people seem to like it." The song was given to Bud Flanagan, who performed it for four years in Together Again, a West End revue produced by the bandleader and impresario Jack Hylton. The song has since been performed by such non- Londoners as Danny Kaye and Arthur Askey, and much later was given new lyrics by Gregg for a duet between Kirk Douglas and Burt Lancaster on Parkinson.

In 1951 Gregg directed Agatha Christie's first stage success, The Hollow, and went on to direct stage versions of several of her mysteries, notably The Mousetrap. Gregg directed the first version in 1953 and presided over the cast changes until 1960, by which time he was fed up with both Christie and the play. "She was a mean old bitch," he would say. "She never even gave me the smallest gift." He wrote a book about his experiences, Agatha Christie and All That Mousetrap (1980).

In 1952 he had written a song for the Coronation, "Elizabeth", saying that the new queen had "more magic than spring", but he was generally more interested in writing musicals than individual songs. In 1962 his musical version of Jerome K. Jerome's Three Men in a Boat was broadcast on the BBC Light Programme, the three men being Kenneth Horne, Leslie Phillips and Gregg himself.

His film appearances included parts in Doctor at Sea (1955) with Dirk Bogarde and Simon and Laura (also 1955) with Kay Kendall and Peter Finch. He was one of the voices in Walt Disney's animated Robin Hood (1973). From 1970 he presented one-man shows around Britain about his theatrical and musical life.

For many years, Gregg took part in BBC light entertainment shows, notably nostalgia quizzes and in 1972 he became the presenter of Thanks for the Memory on Radio 2, which offered a panoramic view of popular music before 1950. His last programme was broadcast a month ago.

Spencer Leigh