It is known in the industry as the "Martha Wash rule", litigation by the legendary disco diva in the early 1990s establishing the principle that invited vocalists on records are entitled to insist on a full artist credit even if they are not regular members of the acts in question. It is principally for that reason that at least 13 of the Top 40 singles this week all feature the f-word - featuring - in their credits.
There are however occasional exceptions to the rule, which explains why this week we have the extraordinary situation of a singer enjoying what the record books will tell you is his first ever Number One hit single but which is actually his second. Californian singer Aloe Blacc first came to attention with his 2010 single I Need A Dollar which was a huge success across Europe, escaping finally to Britain over a year later to eventually become a Number 2 hit in early summer 2011. He remained a one-hit wonder, but for his contribution both in writing and vocally on the Avicii single Wake Me Up for which he received no direct credit but which nonetheless spent a fortnight at Number One in July last year.
This week Blacc returns to the charts under his own name for the first time in three years and lands an easy Number One single with the memorable track The Man, a track taken from his latest album Lift Your Spirit. For the second time in three weeks the Official UK Singles chart plays host to a song at Number One which unashamedly borrows lyrics from an older classic, in this case, The Man paying homage to Elton John's first ever hit single Your Song, the track thus giving Elton John and Bernie Taupin their first Number One hit as songwriters since 2Pac's Ghetto Gospel hit the top in July 2005 (although Elton himself co-wrote I Don't Feel Like Dancing for the Scissor Sisters a year later and has thus topped the charts more recently).
Those paying attention will note that Blacc's single is the eighth different track to top the charts in as many weeks, the longest run of unique one week Number One hits since the summer of 2011. However of all the singles to have had just a week of glory of late, not has suffered quite the ignominious fate of last week's chart-topper She Looks So Perfect by 5 Seconds Of Summer. Suggesting that the appeal of the track was almost totally confined to their dedicated online fanbase, the single takes a dramatic 1-10 chart tumble, the biggest fall from Number One single McFly's Baby's Coming Back/Transylvania slid a record-setting 19 places from the top of the charts in May 2007.
Speaking of guest stars, Swedish singer John Martin has had three credited Top 10 hits to date, all as the featured act on singles by others. He thus makes what is effectively his solo debut this week with Anywhere For You which lands at Number 7. His biggest hit single to date is the Swedish House Mafia track Don't You Worry Child which topped the charts at the end of 2012. Although the record books note that the single was his first chart credit, he was also the featured singer on their 2011 single Save The World - this time without asserting his Martha Wash rights. See how confusing it can get?
Scottish soulman Paolo Nutini has been absent from the charts since the release of his second album Sunny Side Up in 2009, its most notable hit single being Pencil Full Of Lead which peaked at Number 17. This week he lands his first Top 40 hit single since then with new track Scream (Funk My Life Up) which settles at Number 12 to become his highest charting single since his 2006 debut Last Request peaked at Number 5. New album Caustic Love is set to drop next week and rather curiously this is actually the second track from the album to chart, advance purchasers having already benefitted from the instant grat track Better Man which peaked at Number 43 a fortnight ago.
The arrival of the hit Disney film Frozen on DVD and Blu-Ray this week has had a beneficial effect on several songs from its soundtrack, not least of which the Idina Menzel take on Let It Go which has been a singles chart ever-present during the whole process of cinema release, Oscar glory and now home video marketing for the film. The track leaps 27-17 this week to grab its highest chart placing to date, one place higher than the Number 18 it scaled six weeks ago. Also finally making its Top 40 debut this week is Do You Want To Build A Snowman from Kristen Bell and Agatha Lee Monn [credited the voices of both adult and toddler Anna in a nice touch] which leaps 59-40 in its 13th week as a Top 75 hit single, beating the Number 45 peak it had previously scaled eight weeks ago.
A handy performance on one of the live shows of The Voice UK has had a positive effect on Shakira's latest single Empire which rockets 61-25 this week, and also worthy of a mention is the continuing travails of the latest HAIM single If I Could Change Your Mind, the latest in a series of slow burners for the three sisters and which has now risen 52-33-27 in the last few weeks to become their second highest charting single to date, albeit some way behind the Number 16 peak of The Wire from October last year.
At the top of the Official UK Albums chart, an epic tussle is finally resolved in the favour of the Kaiser Chiefs who barge Sam Bailey out of the way with their fifth studio album Education, Education, Education & War. It is their second Number One album, a full seven years after their second release Yours Truly Angry Mob also topped the charts. The success of that album was partially down to the success of its lead single Ruby which gave them their one and only Number One single in February that year. The group have been absent from the singles chart since 2008 hit Never Miss A Beat but this week see Coming Home, the lead single from their new release chart at Number 45. The renewed level of interest in the work of the Leeds group may well be down to the quality of their music, but one suspects lead singer Ricky Wilson's recent role as a judge on The Voice UK is also a fairly important factor.
Finally, there is one last surprise new entry in the Top 40 this week, the sad death this week of house music pioneer Frankie Knuckles prompting a surge in support for his most notorious and surely most famous track Your Love which lands at Number 29 this week. Technically Knuckles was never the performer of the record, that honour going to Jamie Principle who wrote and recorded it as far back as 1984, but it was the support of the legendary DJ plus some production polish which led to the track being re-released in 1987 re-credited to Knuckles himself. The single wasn't released in Britain until 1989 when it made a mere Number 59 but its musical backing will be instantly familiar most thanks to its use by The Source on their famous 1991 remix of Candi Staton's You Got The Love. This posthumous chart appearance for Your Love instantly makes it Frankie Knuckle's second biggest hit single ever as named performer, just behind 1991 hit The Whistle Song which peaked at Number 17.