OTTAWA — Gov. Gen. David Johnston is among thousands of people gathered in London for three days of celebration to mark the Queen's 90th birthday.
He and 14 other governors general had lunch with the Queen after a ceremony filled with pomp and pagentry at St. Paul's Cathedral.
He says one of the topics discussed was the usefulness of having apolitical heads of state.
Johnston says the strength of a constitutional monarchy lies in the stability and serenity it brings, allowing countries to avoid extremes.
The Queen's actual 90th birthday was in April, but tradition allows British monarchs to choose another official date for public celebrations.
Her official birthday is tomorrow and will be marked with a colourful military parade.