Conservative party donors are among the investors in the company that spawned the election consultancy at the centre of a storm about use of data from Facebook.

Filings for SCL Group, which is at the top of a web of companies linked to Cambridge Analytica, show that since its conception in 2005 its shareholders and officers have included a wine millionaire who has given more than £700,000 to the party, a former Conservative MP, and a peer who was a business minister under David Cameron.

On Wednesday, Theresa May faced questions in the House of Commons over Tory links to the company. “As far as I’m aware the government has no current contracts with Cambridge Analytica or with the SCL Group,” the prime minister said.

Downing Street said that Cambridge Analytica had approached the Conservatives about working for the party, but that the approach had happened “under a previous administration”, and the bid had been rejected.

“An approach was made and the party decided not to take that forward,” May’s spokesperson said.

Later a spokesperson acknowledged that the government had previously held three contracts with SCL Group but said that they had ended well before the current issues. Two of the contracts were undertaken under the last Labour government.

Cambridge Analytica hit the headlines at the weekend after it was revealed that data had been harvested for it from 50m Facebook profiles without the users’ permission. On Monday, undercover reporting by Channel 4 News showed the head of the firm, Alexander Nix, offering covert services to a man he thought was a prospective client.

The US firm is owned by the Mercer family and a UK company called SCL Elections, which is part of the SCL Group.

Until 2015, SCL Group was known as Strategic Communication Laboratories. It was only registered with UK Companies House in 2005, but was mentioned in articles in 2000 about the Indonesian elections.

From its outset as a UK-registered company, SCL Group had investors from the upper echelons of British life. Lord Marland, a successful businessman who became a minister in 2010, held shares personally and through two related investment vehicles, Herriot Limited and a family trust.

Marland said that he had not been involved in running the company, and had refused a request to introduce it to Conservative party HQ.

“I have had very little engagement with the company and in fact am fairly sure I have only met Mr Nix once,” he said.

“I also know very little of their operations as my initial investment was over 10 years ago. As such I had no idea of their Facebook data and am naturally concerned about current events.”

Sir Geoffrey Pattie, a former Conservative defence and industry minister, took a key role in the company for its first three years. In a Guardian article from 2005 he is described fronting the company’s stand – which is “more Orwell than 007” – at a defence show in London. Pattie is shown to have resigned as a director in 2008.

One of Marland’s fellow investors, and the person now registered as having “significant control” over SCL Group, is a Conservative party donor called Roger Gabb.

Gabb, who introduced the Volvic water brand to the UK then went on to make millions selling wines including the Kumala label, now owns more than 25% of the company. At its formation he was named as a shareholder, as was the Glendower Settlement Trust which is linked to him and his wife.

Gabb has given £707,000 to the Tories since 2004, making contributions to the main party and his local Ludlow branch. In 2006 he gave £500,000 to the party, making him one of its largest donors at the time.

He was also a campaigner for Brexit, signing letters on behalf of the campaign as a director of Bibendum Wine, and placing an advert in local newspapers. In October 2016 he was fined £1,000 by the Electoral Commission for failing to include his name and address in the advert.

The property tycoon Vincent Tchenguiz was also a shareholder via his company Consensus Business Group. Tchenguiz donated £21,500 to the Conservatives between 2009 and 2010.

For eight years from 2005 Consensus Business Group held just under a quarter of the shares in SCL, which was valued at around £4m at the time of the investment.

The firm said it had no role in the running of the company, and had sold off its stake in 2013. It appears that it received around £150,000 for the shares.

In a statement a Consensus Business Group spokesperson said the company was a minority financial investor in SCL and was never involved in the day-to-day management or its operations.

The spokesperson added: “Consensus Business Group invested in SCL in 2005 taking a 24% stake in the business, on the basis that the company developed a major emergency response and strategic communication centres capabilities for clients.

“SCL was one of many investments made by Consensus Business Group between 2002 and 2008. Consensus Business Group lost interest and began negotiations for exit in 2013 and finally sold its stake back to SCL in Q1 2015.”

Julian Wheatland, a close associate of Tchenguiz, was involved with SCL Group from the beginning, and is still a director at the company.

The other main players at SCL Group are Nigel Oakes, an old Etonian from a military family – his father is Maj John Waddington Oakes – and a former boyfriend of Lady Helen Windsor. Oakes had previously set up a company called Behavioural Dynamics which made many similar claims to SCL about its ability to influence voters. In 2000, it worked for the Indonesian president, reportedly without great success.

Nix, a fellow old Etonian, is reported to have joined Oakes at an earlier incarnation of SCL in 2003. Companies House data shows he is linked to 10 firms, which all appear to be linked in some way.

On Wednesday, the Scottish National party’s leader in Westminster, Ian Blackford, asked May about her party’s links with SCL, which he said “go on and on”.

“Its founding chairman was a former Conservative MP. A director appears to have donated over £700,000 to the Tory party. A former Conservative party treasurer is a shareholder,” he said.

“Will the prime minister confirm to the house her government’s connections to the company?”

May said the allegations around Cambridge Analytica were “very concerning”.