Former deputy speaker of the House of Commons Nigel Evans used his "powerful" influence to sexually assault seven young men, a court has been told.
He had the "ability to make or break" the careers of those who wished to work in Westminster, a jury at Preston Crown Court heard.
Evans exploited his position and pressed his sexual attentions on his victims, and carried on doing so despite being warned about his behaviour, says the Crown.
Evans, 56, faces nine charges in all, dating from 2002 to April 1 last year, involving the seven complainants. The MP for Ribble Valley, in Lancashire, denies two counts of indecent assault, six of sexual assault and one of rape.
Opening the case, prosecutor Mark Heywood QC said: "Within the Palace of Westminster, in his constituency and in his own political party, Mr Evans was, during the decade with which you are concerned, a very well-known and powerful individual.
"Part of his influence included the ability to make, or to break, the careers of those young people who themselves would be politicians or work for those who govern.
"The prosecution case against Mr Evans is that he, often when in drink, pressed his sexual attentions on those younger men, using or trading on his position of influence.
"Now this behaviour did not happen once but has been repeated over time and despite repeated warnings given to him by others.
"It has also escalated in seriousness, no doubt because he believed that his position made it less than likely that someone would complain."
Mr Heywood continued: "The prosecution alleges that he, on separate occasions over many years, has sexually assaulted young men, both in public situations and in private.
"By the last of the these, in early 2013, he raped one of the young men.
"So the prosecution allege, he not only abused those young men, in some cases seriously, but he abused the positions he held.
"Mr Evans, on the other hand, denies the allegations made, he says that in respect of, for example, the rape, events were entirely consensual, agreed upon, or the result of misreading signals or simply that either they did not happen or he has no clear recollection because of the passage of time."
Mr Heywood then began to go through each of the allegations individually.
The first alleged offence happened in late 2002, with the complainant, an openly gay man, aged 27. One evening he was in a busy Soho bar, either the Red Cube in Leicester Place or the Green Carnation, the jury heard, and Evans was also there.
"He had obviously had quite a lot to drink," Mr Heywood said of the MP. "Whilst the complainant was standing talking to someone else he felt a hand going down the back of his trousers.
"The defendant placed four fingers inside the waistband of his trousers, reaching down as far as the web of the thumb would allow.
"So you understand, there was no words, no warning or invitation. The complainant neither wanted nor consented to the act.
"He was shocked by it but, and this is, you will see repeated over time, he did not want to cause a fuss because of who Mr Evans was."
The complainant was "annoyed" but "walked away" and felt "sorrow" at the MP's behaviour because while it was known he was gay, at that point he was not "openly gay" and the wider public did not know this, the court heard.
Mr Heywood said were it an isolated event, never to be repeated, that would have been the end of it. But he continued to tell the jury about the next alleged offence.
The second complainant was assaulted one night at the Conservative Party conference in Blackpool in 2003, in a bar called Number 10 within the Imperial Hotel.
He was drinking with a friend, at some time between midnight and 3am, and Mr Evans was there and described as being "plastered", Mr Heywood said.
Evans stood next to the complainant and "without warning or any kind of invitation" he put his right hand underneath the man's suit and into the top of his waistband He then tried to put his hand down the young man's trousers, the jury heard.
"In fact the impression being given was of someone trying to get his hand down the back of trousers and round the direction of the front," said the prosecutor.
The complainant was aware that journalists were present and "discreetly removed" Evans's hand and stepped back.
Mr Heywood said: "(The alleged victim) was annoyed and embarrassed. He made it clear to Mr Evans that he did not want to be touched in this way."
A member of the Conservative Party Board then stepped in and moved the defendant away from the group. But about 10 minutes later Evans returned and "did exactly the same thing again", said Mr Heywood. "That is, to make a concerted attempt to put his hands down his trousers.
"Again, there was no physical contact with the bottom or genitals, chiefly because he again pushed his hand away."
The alleged victim informed a prospective parliamentary candidate, and an MEP, and was told to sit in the lobby while they dealt with Evans.
The jury was told that it was suggested to the defendant that he was drunk and it was time to retire to bed.
The following morning the complainant said he considered he had been a victim of a sexual assault .But he did not report the matter to the police and was content for the incident to be "quietly resolved" by the party.
Mr Heywood said both men had met on a handful of occasions since 2003 and had never discussed the events at the bar. At the time Evans occupied a "significant political job" as Shadow Secretary of State for Wales but he was later removed from that post by then Tory leader Michael Howard and had not served a frontbench role since, said the prosecutor.