Rio Ferdinand's agent declared last night that the defender was treating as "a joke" the controversy over his being caught breaking bread with Chelsea's chief executive Peter Kenyon at a London restaurant. "Manchester United should treat it like the joke of the century," said Pini Zahavi. "It is the mother of the joke of all jokes."

No one at Old Trafford was laughing, however, after scrutinising the reasons given for their most expensive player driving to London after Saturday's defeat at Norwich City to dine with Zahavi and Kenyon at Carpaccio, close to Stamford Bridge.

The revelations have caused friction between the clubs and Alex Ferguson is understood to be highly suspicious about Chelsea's motives despite their insistence it was a "meeting purely by chance".

"What happened here is very simple," said Zahavi. "Rio came to see me to collect some paperwork and when he rang I was dining with Peter Kenyon. He came anyway, but so what? This was not a meeting as such. Graeme Souness (the Newcastle manager) was also supposed to be there, but he had to pull out at the last minute to be with his team."

Zahavi made as much clear to David Gill, United's chief executive, when he met him in London yesterday for preliminary talks about a new contract for the England international. Ferdinand has two years of his deal to run and negotiations began last month over a deal that would make him the highest-paid player in the club's history.

"Manchester United know the truth," said Zahavi. "It was totally innocent. Do you really think that if I wanted to arrange a meeting between Rio and Peter Kenyon I would do it at Carpaccio on a Saturday night? It really is a joke and that is how Rio is treating it.

"He wants to stay at United and the idea is to extend his present deal by another three years. If he doesn't sign a new deal he will leave in two years to play abroad, which has always been one of his ambitions. But I think he will stay providing the conditions are right."

Kenyon, who knows Ferdinand from when he was the chief executive at Old Trafford, rang Gill to reiterate Zahavi's version of events and assure his former colleague that the meeting was totally innocent.

Nevertheless, Chelsea's track record of being economical with the truth over the Ashley Cole affair (when Zahavi was also prominently involved) means their story will inevitably be shrouded in suspicion.

However strongly Chelsea protest, Kenyon has previous for clandestine meetings with players from rival clubs and Ferguson is entitled to fear the worst, given that Zahavi told the Guardian that the London club wanted to sign Ferdinand as long ago as March last year.

Though he has chosen not to say anything on the record, Ferguson was amazed by Chelsea's gall in meeting Cole in broad daylight at a London hotel rather than choosing a more private location, and would not put it past them to try a similar tactic with one of United's players. He is not alone at Old Trafford in being deeply mistrustful of Kenyon since his defection to Stamford Bridge and is particularly wary of the threat of his players being offered more lucrative financial packages at Stamford Bridge.

Despite his concerns, Ferguson is not believed to have confronted Ferdinand, but, at the very least, it is not unreasonable for the United manager to feel an overwhelming sense of unease that the man he regards as Roy Keane's successor as captain was apparently unaware of how bad it would look to be seen dining with Kenyon.

Ferguson has repeatedly offered his support to Ferdinand despite there being a strong argument that his eight-month suspension for missing a drugs test has caused irreparable damage in two unsuccessful campaigns, and judging by the caustic reaction on their websites the supporters are questioning whether that loyalty is being repaid.

"Overrated Wannabe Sleeps with the Enemy" was the main headline on the fanzine Red Issue, which said of Zahavi's argument that Ferdinand needed to collect some paperwork: "After all, there are no fax machines, postal services or couriers in Cheshire's millionaires' row, are there?"

Despite the controversy and some persistent concerns about the frequency with which Ferdinand returns to London at weekends, United still fully expect him to sign a deal before the start of next season - presumably with a clause included that he avoids Kenyon's favourite restaurants in the future.

"Like all negotiations these things take time," said Zahavi. "There are a few things that need to be sorted out before we can agree anything."