I have a longish layover in London Euston and I have some work to do. Working includes using a laptop, ideally with a power socket, and paper notebooks. Is there somewhere I can work in or near London Euston? I'd be even willing to pay for access in a first class lounge.
Euston Station itself also has free wifi, but power points are tricky and it is super busy/noisy. I would highly recommend the British Library which is just down the road (see the website for a map & opening times). It has everything you need - free wifi (you will need to sign up), powerpoints, toilets, coffee shops. There are even a few exhibits if you want to take a break and stretch your legs.
Just go in, find a seat on one of the many floors, turn on your wifi and log in to the library (BL visitor from what I remember) and follow the instructions. There is a little more info on the website, or when you arrive there is a huge information desk (you really can't miss it).