Media playback is unsupported on your device Media caption Secret filming shows Patrick Mercer signing a contract with the fake lobbying company set up by BBC Panorama

MP Patrick Mercer has been secretly filmed appearing to offer a Commons security pass to a fake firm that paid £4,000 to ask parliamentary questions.

The footage was released by the BBC's Panorama after he resigned the Tory whip over the programme's allegations that he broke Commons lobbying rules.

Mr Mercer said he took the money for consultancy work outside Parliament.

Meanwhile, a newspaper has filmed three peers appearing to offer to be paid lobbyists for a fictitious firm.

They told reporters an all-party parliamentary group could be set up as a lobbying vehicle for the fake South Korean solar energy company, the Sunday Times said.

One of the peers, Lord Laird, said in a statement he had not broken any rules but would be referring himself to the appropriate authorities.

The other two peers have not yet responded to the allegations to the BBC. The Sunday Times said all three had told their undercover reporters at the time that they would declare any payment in the House of Lords register and if they were advocating solar energy either in the Lords or in writing to ministers.

'Coffee invitation'

The Sunday Times allegations come the day after Mr Mercer, who represents Newark, resigned the Tory whip.

Mr Mercer has said he is taking legal advice and has referred himself to Parliament's standards commissioner.

On Thursday, Panorama will air allegations from a joint investigation with the Telegraph - but some of the details were made public on Friday.

Panorama said Mr Mercer had been approached by a fake company set up by the programme, in conjunction with the newspaper.

I do not charge a great deal of money for these things. I would normally come out at £500 per half day, so £1,000 a day Patrick Mercer MP in undercover recording

The fake company, Alistair Andrews Communications, had claimed to lobby on behalf of Fijian business interests for Fiji to be readmitted to the Commonwealth.

The country's membership was suspended in 2009 amid criticism of its human rights record and lack of democracy.

A clip of Mr Mercer being filmed undercover was by Panorama on Friday. It shows the MP meeting an undercover reporter, who was posing as a representative of the fake company.

Mr Mercer can be heard saying: "I do not charge a great deal of money for these things. I would normally come out at £500 per half day, so £1,000 a day."

The undercover reporter replies: "OK, fine."

Panorama said it had paid Mr Mercer £4,000 for working two days a month at a rate of £2,000 per month, but that the money had yet to be declared to the parliamentary authorities.

'Save embarrassment'

Further footage released by Panorama on Saturday shows Mr Mercer telling a reporter - posing as a lobbyist - that getting a parliamentary security pass to someone from the fake firm would require a brief meeting with the MP and standard vetting.

Media playback is unsupported on your device Media caption "I've called in my other pass," Patrick Mercer tells Panorama reporter

In a statement, Panorama said: "Patrick Mercer MP said he agreed to be a consultant for work he said was outside parliament.

"But he submitted five parliamentary questions, which were all answered, as well as an early day motion - all in relation to Fiji."

Patrick Mercer Biography Born in 1956, the son of an Anglican clergyman who went on to become the Bishop of Exeter

Studied modern history at Oxford University and attended the Royal Military Academy at Sandhurst

Spent 25 years as an army officer, serving in Northern Ireland, Bosnia, Uganda and other countries, before working as a journalist

Elected as MP for Newark in 2001

Served as shadow minister for homeland security under Iain Duncan Smith, Michael Howard and David Cameron, before Mr Cameron fired him in 2007 after a row over alleged racist comments

He is married with one son and lives just outside Newark Patrick Mercer Profile

Under parliamentary rules, politicians are required to declare publicly money that they receive beyond their parliamentary salary, but some paid work should not be undertaken at all.

For example, MPs should not be paid "to ask a parliamentary question, table a motion, introduce a bill, table an amendment to a motion or a bill, or urge colleagues or ministers to do so".

Peter Facey, director of the campaign group Unlock Democracy, told BBC Breakfast: "The borderline here is - if you've actually gone and then asked a question, or tabled amendments, or set up an all-party group, where does your financial interest stop and your public interest start?

"And here it's very difficult to tell what the difference is between him being a consultant and him being a lobbyist."

In a statement, Mr Mercer said: "Panorama are planning to broadcast a programme alleging that I have broken parliamentary rules.

"I am taking legal advice about these allegations - and I have referred myself to the Parliamentary Commissioner for Standards.

"In the meantime, to save my party embarrassment, I have resigned the Conservative whip and have so informed [Conservative Chief Whip] Sir George Young.

"I have also decided not to stand at the next general election."

MPs who resign the whip can continue to sit in the Commons as independents but are no longer members of the parliamentary party.

Labour's shadow minister for the Cabinet Office Jon Trickett MP said: "David Cameron must now address his failure to act by working with Labour to establish a Statutory Register of Lobbyists.

"At a time when faith in politics and politicians is at an all-time low, we must all be working hard to reinstate confidence in elected representatives and the governmental system. Examples such as the allegations heard in the last 24 hours are not good for British politics."

A Conservative spokesman said the prime minister was aware of the allegations and thought Mr Mercer had "done the right thing in referring himself to the Parliamentary Commissioner for Standards and resigning the whip".

Parliamentary rules on lobbying All MPs are subject to a Code of Conduct

According to the code they have to register their financial interests, including remunerated employment outside parliament

They are allowed to work as a consultants or be paid for advice

However, MPs are forbidden from acting as a "paid advocate"

A paid advocate is defined as someone taking "payment for speaking in the House"

It also covers receiving payment for asking a parliamentary question, tabling a motion, introducing a bill or tabling or moving an amendment to a motion or bill or urging colleagues or ministers to do so

"It's important that the due processes take their course," the spokesman said.

Mr Facey said: "If you're being paid to give your advice on how to change the law, it has to be wrong. There's a huge conflict of interest."

Parliamentary records show that in March Mr Mercer put down an early day motion - used by MPs to draw attention to issues - saying Fiji was making efforts to restore democracy and there was no justification for its continued suspension from the Commonwealth.

He also asked five questions in Parliament about Fiji's human rights record, UK investment in its public transport and the effects of its suspension from, and government policy on, its readmission to the Commonwealth.

All the questions were answered by Foreign Office Minister Hugo Swire.

The coalition government is committed to setting up a statutory register of lobbyists - companies that seek to influence government policy, often by paying current and former MPs for advice and guidance.

Meanwhile, another Tory MP, David Davies, has said he also met the fake company but refused any business relationship.

Mr Davies, who represents Monmouth, said in a statement he was invited by another MP, to have coffee with "someone who wanted to discuss an issue involving Fiji".

"Shortly into the meeting, the person I was talking to... appeared to offer me a role as a consultant. I told him I did not wish to have any such relationship with him."

Mr Davies said he left before the meeting ended and emailed the man he met later that day saying that "under no circumstances" did he wish to have any kind of commercial relationship with him.

Panorama will be shown on BBC One at 21:00 BST on Thursday.