We tend to use the lines from The Fallen by Binyon

"They shall grow not old, as we that are left grow old: Age shall not weary them, nor the years condemn. At the going down of the sun and in the morning. We will remember them."

Since the second world war the two minute silence is usually then book ended by the words adapted from the Kohima Memorial in Burma "When you go home, tell them of us and say, that for their tomorrow, we gave our today"

Originally, this was always at the 11th, regardless when it fell, and the whole nation fell silent. For economic reasons the parading was moved to the closest Sunday, thus Remembrance Sunday. In recent years, there was a campaign to restore the silence on the 11th, so we now do it twice. The full remembrance parade and services on the Sunday, and a briefer 2 mins silence on the 11th itself.

This 20th and 21st century practice is in contrast to the 19th. Regiments tended to commemorate key actions (and their antecedents still do) like Waterloo Day or Badajoz Day, but not nationally in quite the same way.