It follows reports at the weekend that renegade MI6 officer Richard Tomlinson claimed that a national newspaper editor had been recruited and paid by MI6. Speculation over the identity of the editor has been rife in the media.
Yesterday, Labour MP Brian Sedgemore (Hackney South and Shoreditch) named Mr Lawson as being at the centre of the allegations. "That seems a very odd thing," he said.
"It would be very damaging for the press if it were true. It's an allegation being made by Mr Richard Tomlinson. I have no idea whether it is true but it surely is something we should look at."
Mr Lawson yesterday denied he was an agent for anybody.
A spokesman for the Foreign Office, which oversees MI6, said: "This comes from a now wearily familiar source to us of sensational inventions... we can point out very forcefully that [we] would never have an agent who is the editor of a British newspaper."