What is a good UK-friendly online casino?

In general, it is a licensed brand that meets the needs of the UK market. It has an experienced owner, well-known and established software developers, major banking methods in its cashier, as well as clearly stated bonus wagering requirements and cashout limits and time.

Mr Green and Leo Vegas both have a very strong gaming platform and trustful reputation.
Both are convenient for any device.  Mr Green’s native iPhone app was voted 2016 Casino App of the year by the International Gaming Awards and is also available for Android, via their website. Leo Vegas’ meanwhile, won “Best Native App” at the EGR Marketing and Innovation Awards 2017 and is also top quality with smooth menu design and efficient use of screen space to create an immersive experience. 80+ live dealer games are available here, including 50 tables of roulette alone.

Also worth a shout out are Betfair and William Hill, who both come with solid mobile offerings.