Alex Ferguson has claimed there would be a House of Commons inquiry if Manchester United got as many penalties as Manchester City.
The number of penalties City get at the Etihad Stadium has been the subject of debate for the past two years.
Since the start of 2010-11, they have been awarded 21 spot-kicks.
In the past three games on home soil alone they have got four, two against Aston Villa and one each in the draws with Real Madrid and Everton.
And, ahead of his own side's visit to City on Sunday, Ferguson has cheekily raised the issue.
"The number of penalty kicks they get - 21 in the last year or something like that," said Ferguson.
"If we got that number of penalty kicks there'd be an inquiry in the House of Commons. There'd be a protest."
Bizarrely though, United have had more than City this season, only to miss four of them.
It piles the pressure on referee Martin Atkinson ahead of this weekend's game, which Ferguson accepts has risen markedly in profile since the days when he claimed Liverpool were United's true rivals.
"Liverpool and United games over the last 25 years have been unbelievable," said Ferguson.
"They've always been the most important games.
"It's shifted because at this moment Liverpool aren't challenging for the league like City are.
"City are our biggest threat and we're their biggest threat, so that's changed.
"Their fortunes changed the minute Sheikh Mansour took over.
"We know the minute that happened it was going to be a different ball game altogether.
"But, as we have in the past, we have to accept their challenge like we did when Chelsea came along and
when Arsenal overtook Liverpool in the early 90s.
"We have to do it again."