strange as it seems but there is a new law in UK wherein the only folding bike they will consider when riding british railways is a 16inch wheel bike. good for brompton's business i may say.
Free and unrestricted carriage on public transport (but note that as of 2010, this only applies to bikes with wheels smaller than 20-inch on British railways)
'As of 2010, bikes with wheels of 20-inch and above are no longer regarded as folding bikes, no matter how compact or clever the folding package."
since when was a folding bike considered a non-folding bike. that's why it folds..duhh...