Having spent most of Sunday afternoon queuing in T2 (to no avail) it isn't just a BA or T5 problem.
What I don't understand is where does this HEAVY snow story come from?
“Reduced capacity at Heathrow as heavy snow fell on Sunday“
It would be interesting to get a definition of “heavy snow” used by whomever to explain the situation. Living within 2flight minutes of 9R I struggle to believe it was heavy - just intermittent and only just enough to leave a track on the road, which cleared on the stuff within 30 minutes without the aid of gritting or snow blowers or such equipment.
“Heavy” suggests several inches of the stuff.
Perhaps Sunday staffing had a bearing despite the forecast?