Media playback is unsupported on your device Media caption Grant Shapps speaking on LBC last month: "To be absolutely clear I don't have a second job"

Conservative Party chairman Grant Shapps has said he "screwed up" in a recent interview when he suggested he never had a second job while an MP.

Mr Shapps admitted he had "over firmly" denied continuing his work as a web marketing expert under the name Michael Green, after being elected in 2005.

Labour wants an inquiry into whether his outside interests, which were fully declared at the time, breached rules.

Downing Street said the prime minister had "full confidence" in Mr Shapps.

And David Cameron defended his party chairman in an online interview with Buzzfeed on Monday evening, saying Mr Shapps had made a mistake and it was time to "move on".

In an interview with LBC Radio three weeks ago, Mr Shapps said it was "absolutely clear" he was not doing business as Michael Green while he was an MP, saying "I did not have a second job while being an MP; end of story".

However, Mr Shapps has now acknowledged that he was mistaken over the dates" of his outside employment during the interview.

'Ton of cash'

This came after the Guardian issued what it says is a recording of a sales pitch made in the summer of 2006 in which Mr Shapps, using his Michael Green pen name, says he will be running his "mentoring programme" to hire staff and produce software to create websites, claiming his products could make listeners a "ton of cash by Christmas".

There are no rules banning MPs from having other sources of employment, but they do have to declare any paid employment outside Parliament.

Key dates:

2000: Grant Shapps and his wife Belinda launch How to Corp Ltd

March 2005: The business is incorporated

May 2005: Grant Shapps is elected MP for Welwyn Hatfield

November 2005: Grant Shapps declares his interest in How to Corp Ltd in the Commons Register of Members' Interests

2008: Grant Shapps transfers his shareholding in How to Corp Ltd to his wife. Interest in How to Corp no longer registered in Commons Register

May 2010: Grant Shapps becomes a housing minister

2012: Police decide not to launch investigation into software sales by How to Corp following a Labour complaint

September 2012: Grant Shapps becomes Conservative Party chairman

2013: How to Corp Ltd reportedly dissolved

Mr Shapps' directorship and shareholding in the firm How to Corp Ltd - which featured him under the name Michael Green - was declared in the Parliamentary register of members interest. for 2005 to 2008.

And Conservative sources said Mr Shapps did not regard his interest in his firm as "a second job" - as the company was in the process of being wound up at the time - and more of "a hobby on the side".

They said he had earned minimal income from the job and likened his earnings to those made by other MPs who have written books.

A party spokesman said: "Like many authors and journalists, Grant wrote with a pen name. This was completely transparent: his full name and biographical details were permanently published on the company's main website."

'Re-hashed nonsense'

In his first entry in the register after being elected in November 2005, Mr Shapps declared paid directorships and shareholdings in Printhouse Corporation and marketing firm How to Corp. He continued to declare the paid directorship with How to Corp for several years afterwards, the last entry coming in June 2008.

The source said: "It turns on the semantics of what constitutes a second job."

Defending Mr Shapps, Mr Cameron said: "Grant did have another job when he first became an MP and he declared that in the Register of Members' Interests which is what you are meant to do.

"But he obviously made a mistake by saying in some interviews that the work had stopped earlier than it had. He's put that right so I think we can put that behind him. He's doing a good job."

Conservative colleagues have also voiced their support for Mr Shapps, Health Secretary Jeremy Hunt suggesting the criticism of him was "incredible".

He tweeted: "His sin not to use pseudonym but to write books about how to create wealth - shock horror."

Conservative MP Nadine Dorries said Mr Shapps had "stumbled" in an interview over the exact dates but that the wider accusations were "re-hashed nonsense".

However, Labour MP John Mann suggested Mr Shapps should consider his position as Minister without Portfolio in the government.