[Andrew999]

Today, we mark the launch of The Spider, one of the UK's most popular characters (certainly, when I was ten years old, he was THEEE most popular character in my school)

Created by Ted 'Robot Archie' Cowan and Reg Bunn, most of the Spider's stories were written by Jerry Siegel, arguably his greatest work! (Jerry also gave us the Legion of Super Heroes, another childhood favourite of mine and some other superhero guy who was allegedly drawn to look like him - with his wife drawn to look like a gal named Lois)

For Robb, I should add Jerry also worked with Carl Barks in the sixties.

But today is all about the Spider - and the big question is, why has he never been immortalised on TV or film?

[The Australian Panther]

OK, Anything on Wikipedia at the moment I will grant, but would like at least a second reference to verify.
On Carl Barks

In 1968, he worked for Western Publishing, for which he wrote (along with Carl Barks) stories in the Junior Woodchucks comic book. In the 1970s, he worked for Mondadori Editore (at that time the Italian Disney comics licensee) on its title Topolino, listed in the mastheads of the period as a scriptwriter ("soggettista e sceneggiatore").

Maybe Robb can shed more light on this.
While the entry on the British Spider lists Jerry Siegel as scriptwriter, the entry on Jerry Siegel does not even mention the Spider.

His last work for DC was a short story included in Superman's Pal Jimmy Olsen #89 (December 1965).[18] DC Comics ceased giving him work in 1966, when the company learned Siegel and Shuster were planning a second lawsuit to reclaim the copyright to Superman.[17] He lost that lawsuit.[citation needed]
Siegel again fell into hard financial times after this second dismissal, as he was unable to find regular writing work.

The Spider is a character who first appeared in the June 26, 1965 issue of British comic book Lion,   

   
https://tvtropes.org/pmwiki/pmwiki.php/ComicBook/TheSpider

Can we see the contradiction?

On the other hand:-

He was created by writer Ted Cowan and artist Reg Bunn, and most of his adventures were written by Jerry Siegel, with some by Donne Avenell. The strip originally ran in Lion from 26 June 1965 and 26 April 1969, 

https://ukcomics.fandom.com/wiki/The_Spider

So, putting it together,
[I've just been reading Sherlock Holmes] losing his first legal battle left him in debt and he was only paid a pittance for the spider? Also the court case possibly made him persona non grata in the US and caused him at that time to look to the UK and Europe for work?   
Makes sense I think!
It would also make sense then that

In the 1980s, he worked with Val Mayerik on the feature "The Starling", which appeared in the comic book Destroyer Duck

 
Kirby, Gerber and Siegel worked on that book, which came into existence to defend Gerber in his fight with Marvel over the rights to Howard the Duck.

Here is an interesting article on the Spider, in the context of Tamil comic publishing.
https://downthetubes.net/?p=42115

The Spider has featured recently in a new Brit revival Superhero team, but I can't remember the name right now so can't provide a link.   
Andrew, Thank you!
     

[Andrew999]

Hot on the glorious news of Rebellion's commitment to reprint all the Spider strips beginning next year:

http://www.brokenfrontier.com/spider-siegel-rebellion-tresury-british-comics/

at a very reasonable price - Rebellion have announced they will also collect two John Steel stories from Thriller Picture Library, in COLOUR!

https://downthetubes.net/?cat=10780

It's good to see Rebellion dipping so far into the past - most of their recent revivals have understandably focussed on the eighties - good, but not nearly as interesting as what might be considered the UK's golden age of 1956-69.

Now, if they would only reprint some of those Cliff Richard strips from Valentine, it would solve my problem of what to get my sister for Christmas!