"Portsmouth" is a traditional English folk dance tune, similar to an Irish or Scottish hornpipe melody. It is sometimes referred to as the "Portsmouth Hornpipe".

"Portsmouth" appeared in the 11th edition of John Playford's The Dancing Master in 1701. It is also one of the three arrangements on which English composer Ralph Vaughan Williams based his Sea Songs, originally arranged for military band in 1923 as the second movement of his English Folk Song Suite, and subsequently re-arranged for full orchestra in 1942 by the composer. In the 1950s it was used as the signature tune for BBC television series Billy Bunter.

Popular musician Mike Oldfield recorded an arrangement of the instrumental in 1976. Released as a single, it is Oldfield's highest charting single in the United Kingdom,where it reached number three.

In an attempt to repeat the success of his previous year's Christmas hit, "In Dulci Jubilo", Mike recorded another traditional folk melody dating from 1701 (first known publication), again using Leslie Penning on recorders. The single was just as successful as its predecessor, charting at number 3 in the UK, and became his first non-album single to be issued in the USA. It also charted at number 19 in Ireland. Mike Oldfield plays acoustic guitar, accordion, mandolin, ARP string synthesiser, tambourine, kettle drum and bodhran (Irish drum), and both Oldfield and Penning are credited with "feet".

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