Parliament’s standards watchdog has turned down a request to investigate a senior Conservative MP over whether he used his role on the Commons Treasury committee to lobby for changes to City rules. The parliamentary commissioner for standards, Daniel Greenberg, said a request submitted on behalf of campaign group Unlock Democracy had not provided any evidence that John Baron MP was not acting in the public interest, or breached any rule related to lobbying, that would be sufficient to justify opening an investigation. Greenberg said he had considered the submission “carefully” and was “satisfied that it does not provide a basis for me to open an investigation into John Baron MP’s conduct”, in a written response to the complaint. Baron said in a statement: “I was confident this would be the outcome, as I have always declared all my financial interests, cited them when appropriate, there was never any personal gain, and I have always acted strongly in the public interest in trying to resolve this misleading cost disclosure issue for the benefit of all investors and our economy.” Baron is co-owner and chief investment officer of Baron & Grant Investment Management, as well as MP for Basildon and Billericay in Essex. He has a stake of more than 15% in the company, and receives £500 each month for five hours’ work – interests that he referred to in Treasury committee meetings and has declared in the parliamentary register. The rules Baron would like to see change involve the way investment trust costs are disclosed to consumers, as part of UK rules being drawn up by the Treasury to replace EU legislation post-Brexit. Critics say the rules are misleading, unnecessary and make investment trusts appear more expensive than other funds. Tom Brake, director of Unlock Democracy, wrote to the parliamentary commissioner for standards in late March calling for an investigation into whether Baron broke the code of conduct for MPs concerning lobbying. Brake is a former Liberal Democrat MP and served in David Cameron’s coalition government. However, Greenberg said the complaint did not provide sufficient evidence to justify opening an investigation that Baron had “failed to base his conduct on consideration of the public interest, or has resolved a conflict between his personal interest and the public interest in favour of the former”. The commissioner said it also failed to show that Baron had “breached any rule relating to lobbying”.