British History/ocean travel in late 1800's
When a ship docked in London, were passengers required to immediately disembark? How did relatives know the ship had arrived? Were passengers supposed to go to an Inn or boarding house until they were collected or remain on board. What happened if no one appeared to collect a woman or child returning home from a military post in India.
Yes, passengers had to disembark immediately upon the ship's docking in port. From the 1840s we had the telegragh which meant that people could announce their arrival by telegram. They would usually put up in a hotel if the ship docked late in the day or if they were awaiting collection by family. Otherwise they would take a train out of London the same day.
A ship's arrival date was publicized, but of course bad weather or engine trouble could delay it. Once a ship from India was getting close telegraph stations in France, Spain or Portugal would send news ahead of a likely arrival date.
Lone women or children would simply have to wait for someone to pick them up.