Just saw this thread - http://www.flyertalk.com/forum/showthread.php?t=622740 - on the Air Canada board and thought it was worth flagging...

In summary, Air Transat have got two slots a week to fly LHR-YYZ. Flight departs Toronto at midnight and departs Heathrow at around 4pm.

I know, I know, yadda yadda, no impact, limited frequency, not a proper airline, but it's surely going to make an inroad to BA's WT+ leisure market.