It is weird that the article does not name the airline involved. Should it be pretty much implicit based on the Heathrow-Glasgow city pairing?
I'm more of a colonial a.nutter.
Here's the report: http://www.aaib.gov.uk/publications/bulletins/october_2012/airbus_a321_231__g_euxl.cfm
It was a British Airways A321.
aaib.gov said:Date of occurrence:20 December 2011