When browsing the Lastminute website, I spotted this notice at the bottom.
"lastminute.com", "lastminute" and the colour magenta are all trade marks owned by Last Minute Network Limited and/or its group companies
Bizarrely it turns out that trademarking colours is possible. But we’re OK, we can all continue to use the colour so long as we aren’t in the same business as Lastminute, which is, er, selling pretty much anything. Oh.