The House of Commons has been criticised for launching an investigation into the source of a Sun story showing an MP playing Candy Crush during a meeting.
The Sun published pictures of Tory Nigel Mills enjoying the hit computer game during a Work and Pensions Committee evidence session.
A source said they had seen the Amber Valley MP playing the game over a period of two and a half hours.
Mills told the newspaper: "It was a long meeting on pension reforms, which is an important issue that I take very seriously.
"There was a bit of the meeting that I wasn't focusing on and I probably had a game or two.
"I shouldn't do it but if you check the meeting I would say I was fully engaged in asking questions that I thought were particularly important in how we get the pensions issue right. I shall try not to do it in the future."
A Commons spokesman said the photograph broke strict parliamentary rules.
Taking such unauthorised images can lead to individuals being barred from the estate.
"This was a breach of the filming rules for House of Commons Committee Rooms, and will be investigated by the Serjeant at Arms," a spokesman said.
The committee met last Monday and was discussing pensions and the insurance industry ahead of the Chancellor's Autumn Statement announcement.
Commons rules state that: "No one should photograph, film or sketch or have their voice recorded anywhere within the Parliamentary Estate without permission.
"Anyone who attempts to do so, or to market, publish or transmit such material will be referred to Black Rod or the Serjeant at Arms.
"This could prejudice their future admission to the Houses of Parliament."
Journalists and others have criticised the decision to investigate the leak on Twitter.
Sun managing editor Stig Abell said: "Sun runs good story about MP playing Candy Crush. Parliamentary response: hunt the whistleblower. What is wrong with these people?"
Investigation of a whistleblower who filmed an MP playing Candy Crush rather than the MP himself is barmy. http://t.co/GHfvLHGbLf
— A Peeb (@a_peeb) December 8, 2014
Commons authorities will NOT look at Candy Crush MP Nigel Mills' actions but instead how pictures were taken. http://t.co/b5psP2XO0X
— John Leyden (@jleyden) December 8, 2014
So the MP who played Candy Crush during a House of Commons meeting won't face investigation – but the person who filmed him will. Speechless
— Phil Wilkinson (@PWilkinsonWIG) December 8, 2014