Emails dating back to April, obtained by the Guardian, appear to undermine Liam Fox's claim that his controversial meeting with a businessman in Dubai was a result of a chance encounter at a restaurant.

An email from 5 April shows that the defence secretary's friend, Adam Werritty, met Harvey Boulter, the chief executive of a private equity partner of the MoD. In the email, Werritty says "very good meeting you [Boulter] in Dubai".

Boulter told the Guardian on Saturday night that he first met Werritty to arrange a meeting with Fox in April.

Fox told the BBC on Saturday: "Actually the defence ministry representative asked for it [the meeting] when they happened to be sitting at a nearby table at a restaurant."

He said he was on his "way home" from Afghanistan and made the stop-over to switch from military to civilian aircraft.

Fox was speaking to the BBC during a visit to Libya, which has been overshadowed by the controversy surrounding his links to his former flatmate and self-styled adviser.

Fox's declaration that the meeting was accidental comes after emails obtained by the Guardian showed that Werritty had tried to set it up. Further emails appear to show that Werritty's attempts to set up a meeting date back to April.

The correspondence is between Werritty and Boulter, the chief executive of Porton Group, a private equity partner of the MoD.

On 5 April, Werritty refers to a meeting between Fox's self-styled adviser and Boulter in Dubai. He thanks Boulter for the information on "two issues" discussed which he promises to "push along as discussed".

It is understood that Boulter subsequently expressed concerns to Werritty about the possibility of a legal battle about technology developed in partnership with the MoD.

Boulter's private equity firm and the MoD innovation unit sold technology called Acolyte, designed to help the fight against MRSA infections, to US conglomerate 3M. A dispute about the technology led to 3M refusing to pay the full agreed fee for the deal. Sources say Boulter was keen to meet Fox to get him to press 3M to pay him the rest of the money.

On 19 May, Werritty emails Boulter to say he had "passed this [Boulter's concerns about a legal battle] to one of the Special advisers and I'd hope they'd want to make an issue out of this but that's about all I can do on this".

Harvey Boulter told the Guardian late on Saturday about an April discussion with Werritty about arranging a meeting with Fox.

"I met Werritty in April when I first presented this [legal battle over MRSA technology sold to 3M].

"Werritty and I discussed setting up a meeting with Fox. He [Werritty] said he would with Fox at some point in the future," Boulter said.

Boulter said he met Werritty over dinner in Dubai on 15 or 16 June.

"I bumped into him in the restaurant and he offered to set up the meeting with Fox, because he said he [Fox] was in town.

"The fact that a meeting was going to happen was pre-arranged in April. A meeting with the MoD doesn't happen by chance. I'm sure I wouldn't have just got to meet him [Fox] unless I'd been pre-briefed."

An email seen by the Guardian, which is dated 7.49pm on 16 June, Boulter, who lives in Dubai, invites Werritty to his house, which is 15 minutes from the Shangri-la hotel where he is staying. He offers to send a car for "you and boss".

At 9.55am on Friday 17 June Werritty replies to Boulter to tell him he would prefer to have the meeting at the hotel on the "41st floor lounge".

Boulter has already gone public about the meeting with Fox before the defence secretary claimed it was accidental.

Boulter has confirmed he met the defence secretary shortly after the email exchange with Werritty on the Friday morning.

Reacting to the publication of emails, Labour's shadow defence secretary, Jim Murphy, said:

"Liam Fox's claim that his meeting in Dubai was accidental lasted merely a matter of hours.

"This issue has gone from being embarrassing to being controversial and has now moved way beyond that. This will cause alarm bells to start ringing even more loudly in Downing Street.

"The secretary of state's version of events appear to be unravelling and he now has even bigger questions to answer."