I'd like to know this too... external examining is crap pay for the workload and only paid once a year. Personally I do agency work as I'm a healthcare practitioner but it's hard working essentially two jobs.
Would be good to know what everyone else in academic roles are doing..

Could you do tutoring? Online, via zoom?

consultancy?

I’m an editor at a journal, I get £1500 a year for that. i also do 2-3 vivas a year which is another £500. Not much though.

I review grants for the French resesrch councils and the EU (horizon) which pays quite a lot - about £800 a year all in.

finally, if you are in science you can get approached by consulting firms. I do a bit of this for £300-400 per hour for phone calls to give my expertise! To do this really spend time on your linked in profile.

Examining (ie marking) for the University of London programme? It's reasonably well paid and there are a few different types you can do - at least in my subject there are regular exams, dissertations and a study skills project.

Look up assistive technology trainer and autism mentor. A lot of agencies will pay £30ph plus for remote working. It is usual to have a contract where you paid for the full session if a student cancels with less than 24 hours notice. A lot of student cancel within this period. I’ve ‘worked’ many a Friday where I’ve been paid for the full day and did my own thing.

I wrote a novel, based loosely on my academic interests. It was partly for pleasure, really, but also because I wanted us to have a bit more of a financial cushion (I have some home renovations I would really like to do, I want to take my parents and brother and his family on a big multi-generational holiday, back to the place we holidayed as children) plus this sense that I had a story to tell.
By chance (an author friend read the beginning of it, loved it, and showed it to her agent, who loved it), I ended up with an agent. We are just getting to the point where the agent will start to sell it, so who knows, but the agent thinks it is really marketable and that there will be a lot of interest. Her hope is that it will sell for at least twice my annual salary, perhaps up to five times.
I think I have several other books in me (fiction, whether I have another academic book in me is another matter...) so we shall see.

Personally I match bet. I don't even do it that much and make £8k a year

The last couple of years I had a few invited talks abroad and I was pleasantly surprised to discover that there was a fee for the talk (apart from expenses) - in the UK my experience is that it's expenses only, and sometimes I've been lucky to get even that.
I have also written articles for non-academic magazines/blogs in my area as well as appeared as a guest in podcasts and Youtube streams. A couple of times I saw calls for pitches on social media, put forward my pitch and was accepted; other times I was approached directly.
These are both quite unpredictable things, and I am not even sure that it would be worth it to pursue them more aggressively - I could spend more time sending pitches and trying to build relationships with editors but then it is not as if there are so many publications that I could get a couple of guaranteed commissions per month. Still, it means talking and writing about your research or your discipline, so it is not as if it's grunt work, and it's also the kind of things you can count internally towards promotion under the guise of "esteem" or "public engagement".

Slightly random question @Ruthietuthie how long did it take you to write your novel alongside your 'job'? I'm about to go academic FT but also want to finish a novel that also draws on my interests. (Some conflict here as I feel I should be using the time to write a NF book on my interests - can't see me having time for both...). I think I am totally bogged down in the research for the book though and just need to bloody well get on with the story.

@Acinonyx2 , it took me about a year, but only working a few hours a week, here and there. I was also on sabbatical and more focused on finishing my academic book, so while my time was my own, I didn't dedicate hours a day to it. I found it surprisingly easy, much easier than academic writing for me. You should definitely do it. I nearly fell off my chair when my agent told me what they estimate it may sell for.

I also do reviewing for EU funding agencies. It pays very well, but goodness, it's hard in the first year, when you're still getting used to the very precise way of writing your assessments. In subsequent years I've managed to make over a couple of grand.

I've also learned to always ask for a fee for talks. Worse that can happen is they say no, and I say in response that I cannot spare the time from my day job. Long term, who knows, and organisations will start to value our time properly (though the BBC is a lost cause: they expect you to do stuff for the glory of being on the BBC).

Yes the EU reviewing was them approaching me. I think I'm on their radar as I've had funding in the past. Having said that, I do recall filling in an expression of interest a few years back, so worth checking the site to see if that's an option.

Book proposal reviewing can be well paid. Again, don't do stuff for free when they're making a profit, it's bad enough the fee-gouging journal publishers make money from our sweated labour, but that system isn't going to be fixed soon. Don't get me started on the con of paying for gold open access...

You need to register as an expert on Horizon - if you google you should find it

That rings a bell. Thanks.

What discipline are you in, OP?

There are serious, serious opportunities for consultancy and related things in STEM subjects. Your university might limit the number of days you're able to do consultancy per year. But if you set yourself up independently then there's no reason for them to ever know how much you're doing.

DP does consultancy which brings us an extra £50,000-ish per year. He's also been an expert witness in legal cases involving IP infringement which pays very, very well but is quite niche. DP didn't go through a consulting firm - he set himself up as a consultant and found/generated his own work through making connections with people in industry.

It depends what field you're in though - I'm a social scientist and my opportunities for consultancy are basically zero

Here's some info on being an external examiner [marker] on the University of London international programme www.london.ac.uk/support-examiners. This is the list of courses offered: www.london.ac.uk/courses. If you scroll down to "Academic Leadership" and then open up that section you will see the name of the academic who is actually in charge so I would contact him/her if you're interested.