No Warning To CC
 

I was on a flight recently from LHR to JFK and before all the cabin crew were in their seats the aircraft had started its take off roll and they had to run to the galley. There was no announcment from the cockpit to warn them and i was wondering if this happens often?

No, it doesn't happen "often", in fact it should never happen.

In my airline the flight crew would endeavour to give us a "double ding" (recycling the seatbelt sign) to inform us that we're lining up for take off, however this is not intended as a rule as they might be really busy and not have the time to. Each cabin crew member is obliged to take their seat as soon as the cabin secure procedures are completed and the checks passed onto the senior crew member. At this point the SCCM makes the PA "Cabin crew take your seats for departure" and after that they can get up exclusively for a safety related issue that requires their immediate attention on the spot. Distribution of blankets or drinking a cup of tea in the galley isn't one of those situations!:ugh:

In a nutshell: it's the crew's responsibility to be seated for take off well in time.

FBW

And in my company - I receive checks that all the crew are seated BEFORE I give Cabin Ready to the Flight Crew

Unless the cabin crew gave the cabin secure and crew seated checks. Then decided to get up and move around as they thought they were safe to do so - which is very naughty!! :=