One of England’s top rugby clubs hired a private detective to investigate extraordinary claims of debauchery during an end-of-season riverboat party.

Wasps players booked the Hurlingham floating nightclub for a cruise along the Thames, but their riotous behaviour is alleged to have left staff in tears and fearing for their safety.

Boarding at Richmond, South-West London, just after 2pm, the 42-strong party included England player James Haskell, who is dating Chloe Madeley, the daughter of former daytime TV stars Richard Madeley and Judy Finnigan.

Wasps Rugby Club is said to have hired a private detective to investigate allegations of 'riotous' behaviour at the players' end-of-season boat party, attended by England international James Haskell, pictured with girlfriend Chloe Madeley

The party was booked on the Hurlingham floating nightclub, pictured, on the Thames

Included in the party was stripper Keri Graham, 47, who once performed a lap dance for Simon Cowell on Britain’s Got Talent.

They joined six crew members, including two female bar staff and a DJ, and were immediately given welcome cocktails.

According to Ms Graham, some players took part in a ‘weird’ sexual forfeit involving beer bottles during the party, which was arranged by the players, not the club.

While she was not involved herself, Ms Graham said in a statement, taken on behalf of the club by a detective, that the game left her feeling sick.

Others were said to be disgusted, and at one point it is claimed a barmaid burst into tears and had to be comforted by one of the crew.

The club brought in private investigator William Merritt after being confronted with these and other allegations by agents acting for the boat operator, Out On The Thames.

Merritt, a former New Zealand detective, was asked to establish whether the people making the claims really existed.

Stripper Keri Graham, pictured, was also understood to be at the event

He established they did and, with the club’s agreement, contacted Ms Graham.

Set against the statements taken from the boat crew, which have been seen by The Mail on Sunday, her testimony paints a less disturbing picture of what happened on board the Hurlingham as it cruised along the Thames on May 8.

Coventry-based Wasps, one of the oldest clubs in the game, are second in the Aviva Premiership and will be highly focused today when they take on old rivals Harlequins.

But in May, having played their final league game of the season a day earlier, the players were clearly in the mood to let their hair down.

Ms Graham details several incidents of a lewd nature.

Of her own performance for the players, she said: ‘It would be classed as a risqué, naughty show and only the type of show you would do in front of a group of men.’

Staff had been told wives and girlfriends would be in the party but the only woman in the group was Ms Graham.

Two more strippers had been booked but apparently backed out at the last minute.

It is not claimed all the players were involved in what then allegedly ensued, and according to witnesses some clearly disapproved.

‘For the first hour we were all at the front of the boat looking at the sights,’ said Ms Graham in her statement.

‘It was a warm, sunny day. Everyone was having a good time and drinking. No one was drunk at that time.

Ms Graham, who once performed a lap dance for Simon Cowell on Britain's Got Talent, pictured, alleged some players were taking part in 'weird sexual forfeits'

She then did her show.

In her statement Ms Graham denies having sex with any of the players and said: ‘None of them touched me’.

She added: ‘The guys were amazing and they have since reimbursed me for my bra.’

However, a spokesman for Eye Candy UK, the agency that booked Ms Graham for the party, claimed she was ‘horrified’ by what went on.

Last night Wasps denied the allegations but declined to comment.