A very straightforward cereal promotion, featuring six different sheets of transfers. The advert implies there was only one "Background Scene", at least if we assume that the one shown in the advert is actually just a variant of the one printed on the packet backs.
The front of the Sugar Smacks packet featured the same design of "Mr. Spock" for quite a long time, through several different promotions, with just the badge at the bottom right adapting to illustrate the change in promotion. It looks as if this "Klingon Invasion" promotion didn't last very long.
The ads ran in a few comics on the 13th & 20th February 1971; after extensive searching of over two dozen different comics titles, we could only find it in these issues:
Sally, 13th February 1971 (full back page, in colour)
Buster, 13th February 1971 (full back page, in colour)
Tiger & Jag, 13th February 1971 (full back page, in colour)
The Victor No.522, 20th February 1971 (full page, in black-&-white)
The Hornet No.389, 20th February 1971 (full page, in black-&-white)
So not only was it short-lived, but also not very heavily publicised. It's interesting that one of the comics chosen for the promotion was "Sally" — but of course girls not only have brothers, but also are perfectly capable of enjoying Star Trek (even back in the barbarous wastelands of 1971).
The copy of "Sally" we have in the SPLAT Scan Archives is slightly creased, so for the ad shown above I've used a scan very kindly provided by Matt of BusterComic.co.uk.
As you can see, the black-&-white version is identical to the colour.
We don't have any of these cereal packets in the Archives, but Peter Rice of peterice.com (who trades on eBay under the ID "heatedseats" — hence the labels!) generously allowed us to use his scans of a pair of packet backs (with their fronts) which he was selling. The white squares are the envelopes containing the transfers. It seems that the right-hand packet is a larger size than the left-hand, since although the background panel artwork is identical, it reveals more stars & boulders.
He also flipped the panels over so that you can see what the inside of a cereal packet looks like! I know how much you enjoy this kind of thing…
I expect you'd like to see what was actually in the packets. So here's the front of a packet close-up, followed by the transfer sheet after having been removed from the packet. Although we only have one of the six sheets in the SPLAT Scan Archives, we've been sent photos of the other sheets by various members over the years, so you can get an idea of the whole range.
Picture Credit: The SPLAT Scan Archives — Matt of bustercomic.co.uk — Peter Rice
© Tom Vinelott 2017