What is a good posture for meditation?

"Please sit very comfortably that's very important. There should be no strain on a particular part of the body, for example when you are sitting sometimes your feet might feel little bit numbed down you can change the posture you need not carry on with any extreme effort or any discomfort to yourself, that's first thing you must remember. Moreover some of the people go into tense postures also by stretching their hands too straight or sometimes going very straight or pushing their head behind, sometimes they bend their heads also bit too much also, sit very comfortably with both the hands on your lap in a very comfortable way, there should be nothing extreme to be done from outside."

Shri Mataji Nirmala Devi - 7 February 1981, extract from Introduction to Nabhi Chakra, Delhi, India.

Shri Mataji on Margaret Thatcher

The other day I was with Mrs. Thatcher. Poor thing, she was so miserable. Yes, she was! You know I tried to sort of put her down, her vibrations. She was very miserable. We were just across the table talking to each other. And what I was doing was to balance her - poor thing, she was very, she's very upset.
- Brighton, UK / May 13th, 1982 

I don't want to frighten you like Mrs.Thatcher does about Russians. That might be imaginary.
June 6th, 1983 UK

Certain good things she is saying like self-restrain and all that. Those things, she's talking good things. But what about herself following this?
- April 1982