The puritan in me is always slightly shocked to see holidaymakers at the airport downing pints of lager at 9am, and I feel a bit the same way about brunch, unless it starts at midday. Why would anyone want to drink so early?
I guess that’s what prosecco is made for. It’s low in alcohol, it goes with sweet as well as savoury food (it has a higher level of residual sugar than other sparkling wines) and it’s almost universally popular. The only thing against the stuff is that it’s such an obvious choice. If that’s likely to bother you – and you might well say, why would it at the price? – there’s always other fizz such as cava, crémant and, of course, champagne (which, by the way, goes extraordinarily well with croissants – go on, try it).