Conservative Party chairman Grant Shapps has admitted to “screwing up” in a recent interview about his second job amid calls for an investigation into whether he breached parliamentary rules.

In an interview with LBC Radio three weeks ago, Shapps had claimed that he only worked as a web marketeer under the pseudonym Michael Green before becoming an MP in May 2005.

He said:

“To be absolutely clear, I do not have a second job and have never had a second job while being an MP. End of story”

However, the Guardian has uncovered an audio recording of the MP for Welwyn Hatfield making a sales pitch in the summer of 2006, where under the name Michael Green he said customers could use his “profit diary techniques to make a ton of cash by Christmas”.

Despite fully declaring his interests in running the marketing company How To Corp in the Commons Register of Members’ Interests between 2005 and 2008, Shapps reportedly used legal threats to prevent discussion about his role in the company and use of a pseudonym. The MP is reported to have used lawyers to force a local constituent to delete an allegedly libellous post on a Facebook group about his use of the pseudonym Michael Green and replace it with an apology that explicitly states that he was not using the Michael Green pseudonym when he was an MP.

Labour has called for an inquiry into whether Shapps’ outside interests, which were fully declared in the Commons Register of Members’ Interests at the time, breached parliamentary rules.

Downing Street has said that the prime minster has “full confidence” in the in Shapps as an MP and party chairman.

Shapps transferred his shareholding in How to Corp Ltd to his wife in 2008, after which he stopped declaring an interest in the company. How to Corp was dissolved in 2014.