Legendary producer George Martin, known as the 'fifth Beatle', has died, aged 90. In a career spanning over five decades, he produced some of the world's most popular songs and albums.

As well as signing and producing the Beatles, he worked with 700 other artistes, including Shirley Bassey and Gerry and the Pacemakers. Below, IBTimes UK reviews some of Martin's greatest hits.

As head of Parlophone, Martin spent the early years of his career producing classical music, musicals, and jazz. He also produced numerous comedy and novelty records. Among them was an album with The Goon Show, which caught the ear of John Lennon, a huge fan of the act.

Here are The Goons' Peter Sellers and Spike Milligan with their irreverent 1955 version of Unchained Melody.

On the look-out for a "fireproof" hit-making group for the label, Martin signed the Beatles in 1962.

On single Please Please Me, Martin's contribution was to speed up what was originally a slow ballad and introduce the harmonica played by Lennon. After recording was completed, he looked over the mixing desk and said: "Gentlemen, you have just made your first number one record".

At the time there was no standardised chart, and the single came in at number one on the Melody Makers and the BBC's Pick of the Pops.

Martin's classical experience was key to creating the orchestral, textured sound that came to distinguish the Beatles as the band developed.

It was Martin's idea to add strings to Paul McCartney's classic ballad Yesterday, despite McCartney's initial reluctance.

Here is the original 1965 studio recording:

His masterpiece 1967's Strawberry Fields Forever from the Magical Mystery Tour album, in which his skilful editing and use of vari-speed turned two widely different takes into one master, was key to the song's psychedelic feel.

In the 1960s, Martin worked with the Beatles' fellow Merseysiders Cilla Black and band Gerry and the Pacemakers.

Their 1963 single You'll Never Walk Alone became the official anthem of Liverpool FC.

Martin also produced several film and television scores, including two of the best-known themes for the James Bond films: Shirley Bassey's 1966's Goldfinger, and 1973's Live and Let Die by Paul McCartney and the Wings.

Later in his career, Martin was one of the most respected record producers in the business, working with artistes as varied as Kenny Rogers, Jeff Beck and Ultravox. In 1997, Martion was chosen as the producer for Candle in the Wind, released by Elton John in memory of Diana, Princess of Wales. The single topped charts in several countries. It became the second best-selling single of all time.