I've been thinking about doing a Captain Britain illustration for the past little while. The second version (the one pictured here) has always been one of my favourite costume designs since I first read Excalibur #1 when it originally came out.
Recently, I've been reading through some of his stories from the mid-eighties, and came across a bit where his sister (before she became Psylocke) took up the post as Captain Britain, ably assisted by Captain UK. So, that gave me the idea of doing an illustration of the three characters together.
Why did I include the Celestial known as Nezarr in the background? I'm not entirely sure, except that I'm now thinking of doing a whole series of these pin-ups with different Celestials in the background.