Given the subject matter, "Deep Blue" also served to convey the suffering endured by the millions of refugees from war-torn Bangladesh in 1971, as sickness and disease became widespread among their makeshift camps in northern India.

[7] Louise was also diligent in replying to her son's fan mail[8][9] and, in the words of music journalist John Harris, she "stood alone among the Beatle parents as an active champion of their talents".

[26] In what Inglis describes as a "poignant contrast" with the composer's Beatles track "Here Comes the Sun", Harrison sings that the sunshine brings him no relief,[25] but instead leaves him "suffering in the darkness", which is "so easy come by on the roadside of one long lifetime".

[11] The lyrics bear out the powerlessness he felt while someone dear to him died,[17][25] specifically in the second verse:[27] When you stand there, watch tired bodiesFull of sickness and pain to show youJust how helpless you really are ...Harrison was at Louise's bedside until her death on 7 July.

[20][29] According to Rolling Stone contributor Mikal Gilmore, he read passages to her from a text about the Bhagavad Gita, "commenting on the sacred book's views of death as a changeover rather than a termination".

[47][48] Author Elliot Huntley suggests that, having been incapable of assuaging his mother's pain as she lay dying in 1970, Harrison gained extra motivation from "a situation his fame and commercial cache could do something to alleviate".

[63][64] The dobro had since become "something of a party piece for him", Leng writes, as "Deep Blue" preceded 1971 releases by John Lennon, Gary Wright and Billy Preston that each featured Harrison "cameos" on the instrument.

[65][nb 4] The only other musician on the session for "Deep Blue", bassist Klaus Voormann, recalls that he, Harry Harrison and Memphis producer Don Nix then travelled to Nashville and explored the American South,[67] before heading to New York for the concert rehearsals.

[72] Before then, Apple's US distributor, Capitol Records, had manufactured one-sided promo discs, featuring just "Bangla Desh",[54] with the result that the lead side had already received considerable airplay in the build-up to the concerts.

[73] The release was accompanied by a trade advertisement that reflected the emotion conveyed in "Deep Blue", of someone watching a loved one "waste away", Spizer writes; in this case, the image depicted a mother attempting to comfort her starving child.

[75] By 11 September, when the single reached its peak position on America's Billboard Hot 100,[76] at number 23,[77] radio programmers had opted for "Deep Blue" and the entry appeared as a double A-side in the chart listings.

[89] Along with "Miss O'Dell", a song he wrote in Los Angeles partly about the Bangladesh crisis,[90][91] it was finally given an official CD release in September 2006,[92] as a bonus track on Harrison's remastered Living in the Material World album.

[94] "Deep Blue" impressed the notably anti-Harrison[95] Village Voice critic Robert Christgau, who considered the song on a par with "Here Comes the Sun" and "My Sweet Lord", while noting its status as a track "hidden away" on a B-side.

[96] In their 2000 book on the four ex-Beatles' solo recordings, Chip Madinger and Mark Easter wrote of "Deep Blue": "The track's understated instrumentation and perceptive lyrical content make this one of the best, yet most overlooked songs in George's catalog.

[99] Theologian Dale Allison recognises "Deep Blue" as Harrison's "musically beautiful and lyrically moving" response to his mother's death, a "prayer to God for help, light, love, and understanding in the midst of personal grief".

[26] Simon Leng sees "Deep Blue" as a candidate for what he terms "the 'last great B-side' accolade", rivalling Harrison's Beatles tracks "The Inner Light" and "Old Brown Shoe".