Liam Fox's claim that Adam Werritty was operating in "a private capacity" when the men met twice in Dubai this year has been thrown into fresh doubt by hotel records seen by the Guardian.

They reveal that Werritty booked into the five-star Shangri-La hotel earlier this year describing his position as "office of Dr Liam Fox" and naming his company as "Atlantic Bridge", the defence secretary's controversial rightwing charity which had close links to a group of powerful American business lobbyists.

Hotel staff said it was normal, but not guaranteed, for the named company to pay all or part of the bill. Werritty also gave a contact address at the houses of parliament.

The official explanation of Werritty's role in Fox's life is being increasingly called into doubt by evidence from countries where the pair travelled.

Politicians in Colombo, the Sri Lankan commercial capital, revealed that they too assumed that Werritty was an official adviser when he travelled there before and after Fox joined the cabinet.

Ravi Karunanayake, an opposition MP in Colombo, confirmed meeting Fox in 2009. "I simply thought he [Werritty] was an assistant or an official or something similar," he told the Guardian.

Channel 4 claimed Werritty was being asked by the Sri Lankan government to help them lobby for arms and aviation supplies, although its sources have not been confirmed.

Lord Bell, whose PR firm Bell Pottinger worked for the Sri Lankan government up until the end of last year, said that Werritty had attended some meetings that his firm had held with the Sri Lankan government but he could not say in what capacity or why he was present.

After a big show of support for Fox in the Commons on Monday, there were some private signs that Tories were still disturbed by what they had heard, and were withholding judgment.

Werritty was interviewed by a senior Cabinet Office civil servant over claims that he may have profited from his close personal relationship with the defence secretary.

It is understood Werritty has claimed that the funding for his trips did not come from defence contractors, but a variety of international Atlanticist philanthropists.

He was interviewed at a location away from Westminster by Sue Grey, the long-standing Cabinet Office civil servant responsible for propriety and ethics. There was no requirement for him to meet with civil servants since he is not a government or Conservative party employee.

But Werritty's willingness to co-operate is essential if Fox is to survive in cabinet as Downing Street has privately made it clear the defence secretary will be in serious difficulties if it could be shown that some of Werritty's income is derived directly or indirectly from his knowledge of Fox's thinking on defence issues, or worse, from his privileged access to Fox's diary.

Last night it also emerged that the prime minister's press secretary, Gabby Bertin, was paid £25,000 by a major US drug company to work as a researcher for Fox's charity while he was shadow health secretary. Bertin, who is now David Cameron's press secretary, was paid by the pharmaceutical firm Pfizer to work for Fox's Atlantic Bridge charity. Bertin was a close colleague of Adam Werritty, Fox's best man and self-styled adviser.

The Guardian also understands that Werritty, 33, will be recalled to give further evidence if Sir Gus O'Donnell, the cabinet secretary, and Ursula Brennan, permanent secretary at the Ministry of Defence, believe they have not had proper disclosure of his business interests, which will be crucial to establish whether he was able to profit from his friendship with Fox – something the defence secretary has denied.

It is understood that the Cabinet Office is asking Werritty to give written details of his income, including some bank statements. The inquiry is being overseen by O'Donnell.

No 10 is aware it cannot afford to be seen to be conducting a whitewash inquiry as David Cameron has courted controversy by refusing to refer the issue to Sir Philip Mawer, the government's independent adviser of ministerial interests.

Mawer is kept on a £30,000 retainer, but cannot initiate an inquiry into a potential breach of the ministerial code unless the prime minister, in consultation with the cabinet secretary, refers the issue to him.

Downing Street tried to stonewall any details about the terms of reference of the inquiry, saying simply that all the facts would be established and all the questions being asked will be put to Werritty.

In the Commons, the shadow deputy leader, Harriet Harman, pressed Nick Clegg to refer the issue to Mawer, saying it went to the heart of trust in government.

She said: "The deputy prime minister has always lectured us on high standards in public office, but while the defence secretary, by his own admission, has fallen short of those standards, the government have failed to refer him to … Mawer.

"Does that not show that they are prepared to sacrifice high standards in public office to protect the secretary of state?"

Clegg replied by implying that the cabinet secretary will decide if Fox has broken the code. He said: "I am very clear, of course, that everybody in this government should abide by the very highest available standards and by the ministerial code, both the spirit and the letter, and that is exactly what the cabinet secretary has been asked to look into and to adjudicate on in his report."

Cameron has said Fox made "serious mistakes" in his ties to his former best man, but appears willing to keep him if there is no evidence Fox knew Werritty was gaining from his numerous contacts with Fox.

According to a list of meetings released by the Ministry of Defence on Monday, the pair met during the minister's visits to Singapore, Abu Dhabi, Dubai, Florida, Bahrain, Hong Kong, Israel, Washington and Sri Lanka. The meetings included one with a senior US general.

Fox said they did not discuss "commercial or defence matters, he [Werritty] had no access to classified documents, nor was he briefed on classified matters".

The hotel records in Dubai seen by the Guardian show that Fox took a room in the same hotel on 3 April, when Werritty was also understood to be staying there.

It was during that stay that Werritty first introduced Fox to the British defence industry businessman Harvey Boulter in the lobby cafe of the hotel.

According to the booking records, Werritty took a room in the 40th-floor executive area which provides exclusive access to the business lounge where he and Fox met Boulter on 18 June in a meeting to discuss a possible defence contract and a legal battle involving the MoD.

It is not certain the booking relates to that occasion. The details relate to 2011 but do not specify the dates he was there, and it is possible Fox was unaware of how Werritty was describing himself. But even if the record does not relate to either of the two meetings Fox had with Werritty in Dubai in April or June, the fact Werritty travelled under the auspices of Fox and gave the Fox-founded charity, Atlantic Bridge, as his company will fuel concern about the proximity of their working relationship.

Additional reporting by Polly Curtis