Where do TV shows obtain instrumentals?

I've notice a lot of shows playing instrumentals into and out of breaks, sometimes over titles too - where do they obtain these? Obviously the instrumental to every song isn't released so it must be from another source.

Commercial music is recorded on various studio audio tracks (more so if its an artist like Phil Collins who played various instruments and sang too, obviously can't sing, play the drums and the violin all at the same time ) - presumably it would be easy enough to isolate the vocal track to generate a "proper" instrumental of that song (Bohemian Rhapsody infamously managed to use more tracks than the studio could handle at the time, something like 24 for the middle "Thunderbolts and lightning" section IIRC). I believe they're supplied like that, a file of various tracks you just chop out a track what you don't need for playout.

Of course a lot of instrumentals are released on the Single, and then you have various instrumentals from other sources that range from "not half bad" to "what the hell is this?"

Simple answer: from the Labels/Producers of the respective tracks and/or Copyright holders.

Further to robharrison’s response, often music publishing companies used to send out ‘promo cd’s’ of upcoming new releases for productions to use. These would normally contain a radio edit and an instrumental.

Nowadays producers of programmes have access to a dedicated website for the music publishers where they can log in, find the track they’re after and download the tracks. The website will show all of the different versions of the track available (most will have an instrumental) and tune ID’s for the production team to include on their MCPS music cue sheets.

They use this https://desktopjukebox.broadchart.com/

The BBC has a blanket licence when it comes to music so they can source and use pretty much anything.

Quite a few broadcasters use that service - https://itvmusichub.ilikemusic.com

It's a handy place to search, if you know exactly what you're looking for - but can also be the most unfriendly search engine in the world.

Interesting that broadchart and ilikemusic are clearly the same white label platform despite having separate URLs.

This FAQ from the BBC version amuses me

How reliable is the service?
The system will be available at all times.

I believe Broadchart bought I Like Music and rebranded as the latter, but someone has obviously decided not to change the URL and put in a redirect.
That FAQ is amusing - I hope someone pulls them up on it next time it goes down!