I think she has probably gone into labour now
Saw a convoy of cars led by the police near Westminster
Just got a hunch
There was a false alarm the other day wasnt there? They denied it, but why else would helicopter and ambulance be at Kensington Palace? False alarms happen to lots of pregnant women and they usually get "twinges" a few days before labour stars for real.
Anyway, we won't know until the baby is born and a sign is placed outside Buckingham Palace.