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It was attended by the Prince of Wales , former Prime Ministers Edward Heath , James Callaghan , and Margaret Thatcher , serving Prime Minister John Major , and also the future Prime Minister , Tony Blair , then Leader of the Opposition .
 Wales, Edward Heath, James Callaghan, Margaret Thatcher, John Major, Tony Blair
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Wales, Edward Heath, James Callaghan, Margaret Thatcher, John Major, Tony Blair