Profile: former Tory treasurer Peter Cruddas
The man at the heart of the cash for access sting was the principal treasurer of the Conservative Party for less than a month before he was forced resign.
Businessman Peter Cruddas founded the online financial services firm CMC Markets in 1989.
He launched the firm with £10,000 and built it into a global player.
The company deals in spread betting, foreign exchange and trading, and has partnerships in more than 30 countries.
It handles over 26 million trades each year and has an estimated value of £1.25 billion, according to the company's website.
Mr Cruddas, who left school aged 15, has amassed an estimated £750m fortune and is 90th in The Sunday Times Rich list.
In 2006 he set up his own charity, the Peter Cruddas Foundation, which aims to help disadvantaged and disengaged young people.
Mr Cruddas was born in 1953, and grew up on a council estate in Hackney in east London, attending Shoreditch Comprehensive School.
In an open letter on his charity's website, he says the decision to leave school early came down to money.
"Dad was a porter at Smithfield meat market while Mum worked as a cleaner and did a brilliant job bringing up three boys; during the war she stayed in London to look after her mum and could have been killed on many occasions."
He bemoans not being given the opportunity to go on to further education "even though I was smart enough and apparently I have an IQ of 155".
And he said the Scouts helped him to "escape a violent home situation".
He said it was the experience of the Scouts that prompted him to set up the charity.
"I found I could achieve things and built up my self-confidence," he said.
Mr Cruddas said he started out as a "dogsbody" on telex machines and "learned the ropes" of trading by working in banks.
He is the largest individual donor to the Duke of Edinburgh International Awards and the Prince's Trust, and supports the Great Ormond Street Hospital.
As a longstanding supporter of the Royal Opera House and The Royal Ballet, he was invited to become a trustee and joined the board of the Royal Opera House earlier this month.
The Arsenal fan became Conservative co-treasurer in June last year, working alongside Stanley Fink.
He took his former colleague's place on the board of the Conservative Party on 1 March.
But he resigned his post on Sunday after secretly filmed footage showed him apparently offering access to the prime minister for a donation of £250,000 a year.