Dating to early 1970 - a tense period when the Beatles were disintegrating - this note offers a former Apple employee both consolation, and an invitation to unload any bad feelings directly to Paul.
John, George, and Ringo had all recently appointed Allen Klein as their manager, leaving Paul somewhat isolated, and it's likely that those feelings, somewhat cryptically expressed here, are a part of his outreach:
'Dear Nigel, In case you are ever worried about anything at Apple - something which you don't feel able to sort out yourself, or maybe something you can't get answered - please feel free to write me a letter at 7 Cavendish Avenue telling me about the problem. There's no need to be formal about it - just say it. The main thing is to keep the lines of communication open. Incidentally, things are going well; so thanks. Yours sincerely, Love, Paul.' Signed "Paul," and with a small sketch of an apple afloat at sea in blue ink, it's a note for which much "between the lines" meanings might be inferred!