The Mike Yarwood Christmas Show

ABBA performed an early edited mix without strings of "If It Wasn't For The Nights" then took part in a comedy sketch of popular UK TV show "The Generation Game" with Mike Yarwood impersonating the host Larry Grayson. Janet Brown impersonated Larry Grayson's co-host Isla St Clair). Then ABBA performed "Thank You For The Music" (backing track recorded previous day in London).

ABBA had recorded the backing tracks earlier with some backing musicians they had brought over specially.  Broadcasting rules required that the backing tracks for any TV performance must not be cadged in any ay from the original record so for a day London's CBS Studios played host to ABBA and three Swedish musicians.

Bearing in mind Agnetha & Björn's marriage had only 3 weeks until they separated, it must have been an incredibly stressful time for them both. Knowing this fact adds poignancy to the programme and especially Agnetha's apparently happy smiles during "Thank You For the Music".

Running order of the show after an amusing opening scene:

1. Janet Brown imitating Margaret Thatcher (sketch)
2. Mike Yarwood imitating US President Jimmy Carter (sketch)
3. Mike Yarwood imitating Frank Sinatra (sketch)
4. ABBA - If It Wasn't For The Nights
5. Christmas Edition of 'News at Ten' with Mike Yarwood as Reginald Bosenquet and Janet Brown as Anna Ford (sketch)
6. ABBA take part in a "Generation Game" spoof with Mike Yarwood impersonating "Generation Game" host (at the time), Larry Grayson
7. ABBA - "Thank You For the Music"
8. Bruce Forsyth's Big Night (sketch)
9. Mike Yarwood closing scene (some jokes and songs on the same spot that ABBA performed "Thank You For the Music")

By the look of Agnetha's hair, could "If It Wasn't For the Nights" have been recorded on a different day to the Generation Game Sketch and Thank you For the Music?  Her hair is curly in If It Wasn't For the Nights and straight for the rest of it.

If you've ever wondered how they managed to have different colours in the background during "If It Wasn't For The Nights", wonder no more. Apparently it was achieved using a technique called colour separation overlay (CSO), a form of blue screen, involving the coloured pieces in the background. ABBA were filmed with multiple cameras and then each camera's input was mixed so that the blue screen elements are replaced with a different colour. After editing and cutting between them you seem to have ABBA performing against multiple backgrounds.
(Thanks to Ken Griffin for the explanation)

A trailer for the programme had ABBA singing "We Wish You A Merry Christmas" which was broadcast on Top of The Pops on Christmas Day 1978.

Read what Charlie had to say from ABBA Magazine No.11:
"During the recording of the show, Benny kept the restless audience entertained, starting off with the Laurel & Hardy theme tune on a beautiful white grand piano and continuing with a medley of 'those' tunes (the ones you know but can't remember the name of).
The audience got another treat when, due to a fault in the first take, ABBA were asked to do one number twice.
"Would you like to hear it again?" Frida asked the audience.
"YES" came a resounding reply.
This time, while the set was being changed, ABBA gave an impromptu performance of "Money, Money, Money."
 

    "If It Wasn't For the Nights"           Generation Game sketch              "Thank you For the Music"
       

Both couples emerge holding hands before the Generation Game sketch. Agnetha is clearly unaware of the camera angles and as soon as she and Bjorn get behind Mike Yarwood, she sharply pulls her hand away from Björn’s. Björn tries to grab it back but she holds both hands firmly behind her back.  This is about the only instance of any possible tension or difficulties in their relationship viewable as they were always so professional.