England rugby star James Haskell presided over a 'kangaroo court' during a party at which players allegedly took part in sexually degrading games in front of horrified riverboat staff.

Holding a whip and wearing a blonde wig and red dress, the then Wasps captain stood at a microphone during an end-of-season celebration on the Thames as team-mates performed 'disgusting' forfeits.

According to a staff member, a young player was humiliated with a beer bottle. Haskell has denied presiding over this incident.

Four members of the boat crew told The Mail on Sunday that separately during the voyage they witnessed players performing sex acts on each other.

England rugby star presided over a sordid 'kangaroo court' on a a debauched riverboat trip with teammates

'None of us had seen anything like it,' said Dean Fergusson, 34, who was in charge of safety on the boat, The Hurlingham. 'It turned into something dark and wrong.'

We revealed earlier this month that Wasps, one of Europe's top clubs, hired a private detective, William Merritt, to investigate the claims. He contacted burlesque dancer Keri Graham, who was booked by the players to perform a show on the boat, and she claimed it was 'one of the best jobs I've ever had'.

But having interviewed Ms Graham and the boat crew at length, we can now reveal what happened.

Ms Graham co-operated with Merritt only because she says she was told that the boat operator, Out On The Thames, was trying to blackmail the club and might traduce her name.

After concluding this was not the case, Miss Graham retracted her statement and now claims the players behaved like 'animals'.

Wasps disciplined an academy player over an 'unacceptable incident', but declined to elaborate; The club complained about blackmail to police, but the allegation was not substantiated.

James Haskell and girlfriend Chloe Madeley

Haskell demanded that staff turn off the boat's CCTV.

His father emailed the boat operator on the eve of the party demanding that 'there is to be absolutely no photography or video records or recordings of any type or nature'.

England player Sam Jones contacted the boat operator and apologised 'on behalf of the boys', adding that 'staff weren't shown the respect they deserve'.

On the day of the party – May 8 – Britain was enjoying a heatwave. Some 40 Wasps players, many in fancy dress, boarded the Hurlingham at Richmond, South-West London, at 2pm. Witnesses said many of them had already been drinking.

Apart from the captain, the only others on board were Ms Graham, Mr Fergusson, a DJ, and sisters Catherine Mahoney, 33, and Chrissey Doe, 39, who were working behind the bar on the middle deck.

Because of the low tide, the boat, which bills itself a floating nightclub, was an hour late and some players made their annoyance plain. 'We gave them welcome cocktails to make up for it,' Fergusson said.

He said England flanker Jones, who made the booking, introduced himself, as did Haskell, 31, who asked him to switch off the boat's seven CCTV cameras. Fergusson said this wasn't possible because of security regulations, but Haskell was insistent and said his father Jonathan had sent an email to the boat operator to make this stipulation. Fergusson pretended to go along with the demand. Footage was taken but later taped over.

The Hurlington on the Thames. Staff were horrified by what they saw as sexual forfeits took place in front of them

Minutes after setting off, the boat pulled into Richmond lock where a topless woman mingled with the players on the open-air front deck.

The lockmaster ordered the Hurlingham to turn the music down and get the woman out of sight of families looking on from an overhead footbridge. 'They were rowdy,' said an onlooker. 'I asked [one of the crew], 'Have they just got on board? Look at the state of them.' '

Next, the players made their way on to the boat's covered top deck where Haskell, standing at the microphone next to the DJ, addressed them. 'He told them that 'kanga court has started' and asked them to pay attention,' Fergusson said.

Kangaroo courts are common in rugby. One website states they allow 'teams to dispense their own mob justice on players for perceived misdemeanours committed throughout the normal season', and forfeits often involve downing drinks.

What happened next – the incident with the young player – left Fergusson and the others profoundly shocked. 'I could see everything because I was standing three to four metres away,' he said. 'This was some kind of forfeit and I got the impression it was because he was new to the team.'

James Haskell was captain of Wasps at the time. One member of staff said the scenes on the riverboat became too much for her

He added that the top deck was left covered in faeces. 'It was really disgusting and we had to get cleaners in afterwards.'

Bar staff Chrissey and Catherine witnessed what happened from behind the bar, and say they saw something similar take place minutes earlier.

'It got too much for me,' Catherine said. 'It was overwhelming. I just didn't understand it. I asked some of the players at the bar why they were doing this. They were just laughing, which made me feel really uneasy.'

Chrissey added: 'I just turned away and said it was disgusting. I wanted to get out. If we weren't on a boat, if we were in a bar or a club, I would have walked out.'

Fergusson said he saw Catherine burst into tears. 'I took her out on the front deck to get some air. She and Chrissey were saying to me, 'Are we going to be OK?' '

All the staff spoke of feeling intimidated, though they stressed that not all the players were involved, and some clearly disapproved.

The party then moved down to the lower deck for Ms Graham's show.

Talented James Haskell celebrates RBS 6 Nations Championship Round 5, Stade de France. He denies being involved in the humiliation of a young teammate

Ms Graham said: 'I realised things weren't going to go as expected when they asked everyone to hand in their mobile phones as we got on the boat. During my show I noticed some of the guys sitting in a line touching themselves.

'I felt horrified. They acted as if it was normal.'

There was a second show towards the end of the three-hour party which, according to the boat crew, led to even more disturbing scenes. Fergusson said: 'It was like they got bored....they told [Keri] they'd had enough of her show.'

The boat crew then witnessed some players engaging in sexual horseplay among themselves. 'We couldn't believe it,' said Chrissey. 'We looked away and I said, 'Let's try to get through this.' We felt trapped.'

The England player demanded that CCTV on the boat be turned off

The captain had intended to take the players as far as Big Ben before dropping them off at Cadogan Pier, Chelsea. But it became clear to Fergusson that they wouldn't make it because of the tide. 'They [the players] were getting annoyed and they surrounded me saying that I was taking the p***.

'I had run out of things to say to them. I am 5ft 6in and 11st 7lbs and I'm stuck on a boat with these 40 massive guys. I was scared.'

When a player overheard Fergusson talking on his mobile to one of boat firm's bosses, he grabbed his arm. 'He said, 'You're not going anywhere because I want to know what s*** you're telling that person.' I was starting to get worried because of all of the things I'd seen and I couldn't wait to get them off, which we eventually did at Chiswick.

'I felt frightened and degraded and the girls felt the same.'

Two days after the party, Jones emailed the Out On The Thames booking agent, Wayne Eldridge, to offer an apology. It followed a conversation they had a day earlier in which Mr Eldridge made clear his displeasure at what had gone on.

However, the boat owners were not satisfied with the apology and entered into negotiations about compensation from the club for 'distress and damage'.

An agent for Out On The Thames initially dealt with Haskell's businessman father, Jonathan, but went to the club directly when he realised he was not an official representative. In an email, Mr Haskell, who acts as his son's commercial director, wrote: 'Instead of being smart and dealing directly with me... you have now very foolishly escalated this nonsense directly to the club... rarely have I encountered someone so stupid.'

Wasps hired a private investigator to look into the infamous riverboat trip. There was 'alleged harassment' on board the boat, and staff felt unsafe

The matter was referred to Wasps CEO David Armstrong and the club promised an 'internal investigation'. It was Mr Armstrong who disclosed that an academy player had been reprimanded.

But he added that the players strongly disputed 'alleged harassment and intimidation of on-board staff or that safety on board was jeopardised'.

In all, three meetings were held between the club, its lawyers and the boat operators. The final meeting ended acrimoniously and on July 28 the club went to the police alleging blackmail, which the boat company vehemently denied.

A Scotland Yard spokeswoman said last night: 'No allegations were substantiated. Our investigation is now complete.'