England’s Rugby World Cup campaign has plumbed surreal new depths after it emerged some members of the squad lost money on shares recommended to them by their kit man. The Rugby Football Union has confirmed to the Guardian it will be launching an investigation amid reports the investment advice received led to disquiet in the camp.

Even by the lofty standards of English sporting stupidity it is hard to recall a more laughable chain of events. According to the Sun on Sunday, it began when the team’s long-serving kit man, Dave Tennison, sent emails over the summer to several members of the team urging them to invest in an oil drilling company called LGO Energy.

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Tens of thousands of pounds are understood to have been invested, with Tennison – known to all as “Reg” – said to have insisted the shares were a sure thing. The share price has instead dropped from £3.27 apiece to 50p, leaving some players facing a significant loss. Sam Burgess was reportedly among the more enthusiastic investors. “Sam Burgess invested the most and was furious when the price went down so much,” a source told the paper. “No one is saying the share tips were the reason we did so badly in the tournament – but it certainly didn’t help.”

An RFU spokesperson said the organisation was taking the matter “extremely seriously” and had launched an internal investigation. Tennison, a former Royal Marine who has been England’s kit man since 2002, was still apparently urging players not to panic about their already faltering investment a mere two days before the World Cup kicked off in September when the shares were listed at around £1.20. “I would not discourage anybody from buying LGO shares at this ridiculous low price,” read one email. “There is absolutely no doubt in my mind that this will prove to be a fantastic investment.”

There is no suggestion the 55-year-old Tennison acted illegally but the England head coach, Stuart Lancaster, and his coaches knew nothing about the emails. England subsequently went out of the tournament prematurely, failing to make it to the knockout stages for the first time following defeats by Wales and Australia.

The RFU investigation into Tennison’s tipping will be separate from the review into the team’s on-field under-achievement. The latter review is in full swing, with the RFU’s chief executive, Ian Ritchie, busy consulting a number of figures within the game after criticism of the make-up of the five-man panel that is due to report to the management board on 17 November.

Lancaster is keen to give his side of the story to the review panel but is also understood to be saddened by Burgess’s decision to return to rugby league with South Sydney rather than fulfilling his three-year contract with Bath.