Labour is calling for an investigation into the conduct and honesty of the Conservative peer Michelle Mone after she repeatedly denied any association with a PPE (personal protective equipment) company it has since emerged she recommended to the government.

The Department of Health and Social Care (DHSC) recently revealed that Lady Mone referred the company, PPE Medpro Ltd, as a potential supplier during the coronavirus pandemic. It was then entered into a “VIP” fast-track, high priority lane for firms with political connections before being awarded two contracts, for face masks and surgical gowns, valued in total at £203m.

Formed on 12 May last year, PPE Medpro was administered and provided with directors by Knox House Trust (KHT), an Isle of Man corporate services firm run by Mone’s husband, Douglas Barrowman.

In extensive correspondence over six weeks last year, the Guardian repeatedly asked Mone about her connection to PPE Medpro. She was also asked whether she had had any discussions with government officials about the firm.

Meanwhile, PPE Medpro was asked if anybody involved in the company had discussions with any peers as part of its approach to the government.

In their responses, neither Mone nor PPE Medpro disclosed that she had referred the company to Lord Agnew, a Cabinet Office minister.

At the time of the correspondence, Mone’s lawyers repeatedly denied that she had any connection or association with the company, or any role in how it secured the contracts.

One of the responses stated Mone and Barrowman “never had any role or function in PPE Medpro, nor in the process by which contracts were awarded to PPE Medpro”. Her lawyers said Mone was “not connected in any way with PPE Medpro” and added “any suggestion of an association” between their client and PPE Medpro would be “both inaccurate and misleading”.

The lawyers also said that “with reference to the ‘high priority lane’ … any suggestion that either [Mone or Barrowman] played any role in how the PPE Medpro contract was processed would be wholly inaccurate and misleading”.

However, last week the DHSC disclosed that Mone had played a seemingly crucial role in the process, by making the initial recommendation to Agnew.

After her referral, Agnew recommended the company to the “VIP” lane for companies referred by ministers, MPs or peers. At that time, the government was awarding contracts with no competitive tender under emergency Covid regulations. Companies referred to the VIP lane were 10 times more likely to be awarded a contract, according to a National Audit Office report.

Angela Rayner, Labour’s deputy leader, called for the government – or the cabinet secretary if the government declined – to publish all correspondence, documents, meeting minutes and notes related to all contracts awarded through the VIP process.

Rayner said: “There are serious questions that Baroness Mone must answer about whether she was telling the truth when she said that she played no role in the awarding of £200m of taxpayers’ money to PPE Medpro. Boris Johnson and the Conservative party also have serious questions to answer about Baroness Mone’s position if she is found to have lied about her role in these contracts and the VIP fast-track lane.

“If Baroness Mone wasn’t telling the truth about her role in these contracts, then she has clearly failed to uphold the Nolan principles and there are further questions to answer about whether she has breached the House of Lords code of conduct. Baroness Mone should refer herself to the House of Lords commissioners for investigation if she is confident she has done nothing wrong and has nothing to hide.”

The code of conduct for members of the House of Lords states that they “should observe the seven general principles of conduct identified by the Committee on Standards in Public Life”, known as the Nolan principles. These include integrity, accountability, openness and honesty, and a positive duty of leadership, which requires members to “actively promote and robustly support the principles”.

Mone’s role in the process was revealed after the DHSC published the list of 47 companies awarded contracts through the VIP lane after a freedom of information request pursued by the Good Law Project, which is challenging the propriety of some government contracts.

There is no evidence that Mone played any part in PPE Medpro securing its contracts last year, beyond her initial referral.

However, this week the Financial Times reported that Mone had also lobbied officials working for the government’s test-and-trace programme, apparently on behalf of PPE Medpro. Jacqui Rock, a senior official, emailed colleagues on 10 February, saying: “Baroness Mone is going to Michael Gove and Matt Hancock today as she is incandescent with rage on the way she believes Medpro have been treating [sic] in the matter.”

Mone’s representatives told the FT that: “In relation to test and trace, she has advocated to government that all companies tendering for UK contracts be treated fairly and that a transparent process is adopted by DHSC in the award of contracts.”

In response to questions from the Guardian, Mone’s lawyers said: “Baroness Mone does not deny the simple act of referring PPE Medpro as a potential supplier of PPE to the office of Lord Agnew.”.

However, they said Mone strongly denied that any of her previous statements were untrue or misleading, saying that they denied her being connected, associated or having a role in PPE Medpro, in the “commercial meaning” of those words. They described Mone’s referral of the company to Agnew as a “very simple, solitary and brief step”, which she did as a contribution to the Covid emergency response.

The Guardian is still awaiting a response from Mone’s lawyers about why the peer initially chose not to disclose her referral of PPE Medpro.