To be fair, she'd never expected to hear that particular phrase as the magical world took care of matters themselves. They had given no indication trouble was brewing. She thought this may be some form of elaborate prank or a security 'exercise'. People from 'that' place also normally didn't enter through her office door.
"Now, see here, young man!" she said with her sternest voice; the one she normally used with her grandson when he'd done something really bad. "I don't know what you're playing at, but I demand to know who told you to say that to me!"
Harry just stared back at her with an expressionless face and quietly said, "You have the code, Ma'am. Please, carry out your orders."
Lady Muriel could detect no subtle signs on the man that he was being anything but completely straight with her. She could detect no sign of subterfuge about him at all. There was no indication of anything whatsoever other than his piercing green eyes. Eyes that told her this young man was to be taken seriously.
Harry felt the lady's stern gaze upon him for quite a while. Then she suddenly rose from her office chair, turned to the door just off to one side behind her desk, and rapped on it twice.
"Enter!" Harry heard a muffled male voice call from the other side of the door.
Lady Muriel opened the door and stepped just inside.
Harry saw her turn slightly to her right and say, obviously to someone within the room, "Excuse me, Sir."
"Yes? What is it, Muriel?" asked a man's voice.
Hesitating a moment Lady Muriel then quietly said, "Merlin Yellow, Sir."
Clearly the man inside was more properly able to restrain himself from verbal utterances of surprise. And a moment later Harry heard the man say, "Send them in."
Lady Muriel beckoned to Harry, who walked forward and past her into the large office beyond.
Inside, Harry could see he was in the Prime Minister's public office. The man himself was standing over near his desk, clearly having just risen from behind his executive desk to greet his visitor. Harry heard the lady behind him step back out of the office and close the door behind her.
The tall man with short grey hair and large horn-rimmed glasses standing at the other end of the office from him stared at Harry and frowned slightly before quickly replacing his expression with a politician's smile.
"Hello, young man," the man said, continuing to come forward. "I'm Prime Minister Major. To what do I owe the pleasure?"
"One moment please, Sir," replied Harry, quickly casting a spell.
The Prime Minister saw the young man suddenly reach outwards away from his body with his right hand and make a few slight intricate motions. Suddenly there was a slight noise behind him.
Spinning around to see what it was the Prime Minister saw that a little trinket on his desk seemed to be dancing a little jig, before it
suddenly flashed with a small bright orange light and fell over on its side.
Turning back to the young man that had walked into his office, the Prime Minister asked, "What was that?"
Smiling and stepping forward, Harry replied, "I just cast a small charm spell designed to detect, and then destroy, any magical item enspelled to act as... what you might call a... 'listening bug'. We will now not be overheard by anyone by magical means."
Listening to what Harry said the Prime Minister lost his politician's smile. It didn't take a Legilimens to see the Prime Minister was not happy about what Harry had just said.
"You mean to tell me," said the Prime Minister in a low voice, "That... that thing was being used by someone to listen in on anything said in this room?"
"Yes, Sir," said Harry. "If I may ask, Sir; who gave it to you?"
Frowning and thinking back the Prime Minister angrily said, "That peculiar man in the green bowler who called himself Minister of Magic."
"That would be Cornelius Fudge, Sir," said Harry. "He's one of the reasons I'm here."
"He gave that thing to me as a gift when I first took office," the Prime Minister angrily mused. "I don't know why I kept it, let alone on my desk."
"If I may, Sir?" asked Harry, gesturing towards the trinket.
Frowning at Harry the Prime Minister also gestured and said, "By all means."
Harry walked over to stand before the desk, waved his hand over the now frazzled little trinket, and said, "Ah! It's enspelled with a charm that encourages you to keep it here. Very clever of the man."
Then, after a few other quick hand gestures, said, "The charm's now been removed, Sir. You can dispose of it whenever you wish."
While Harry was talking the Prime Minister walked over to the desk to stand beside him and watched what he did.
After Harry finished removing the charm the Prime Minister asked,"Is it safe for me to handle?"
"Yes, Sir," replied Harry. "There is no longer any magic associated with it."
The Prime Minister reached over and picked it up. "I think I'll hold on to it," he quietly said. "Minister Fudge and I are going to have a little chat about it."
The Prime Minister walked around his desk, while staring at the object in his hand. Harry could see he was deep in thought.
The pause also gave Harry his opening. "Now, Sir; as to why I am here," he said.
The Prime Minister quickly looked back up at the man before him."Yes; of course," he replied. "Merlin Yellow, and all that."
"Please, take a seat," he said pointing to one of the chairs in front of his desk.
"Thank you, Sir," said Harry, sitting down. "First, I should at least introduce myself... My name is Harry James Potter and I am the... presumptive... Earl of Slytherin."
The Prime Minister sat bolt upright on hearing that. "Earl of Slytherin, My Lord?" he exclaimed. "I'm sorry, I didn't know!"
"No reason you should, Sir," Harry calmly replied.
The Prime Minister then paused to think for a few moments, resettling into his chair and frowning. "I'm sorry for raising this, My Lord; but I've never heard of the Earl of Slytherin before now."
Harry smiled and said, "I'm not surprised in the least, Sir. The title'Earl of Slytherin' has not been in use for almost one thousand years."