The head of the watchdog monitoring standards for holders of public office has called for increased oversight of ministerial interests. The comments from Lord Evans follow controversies concerning ministers’ involvement with lobbyists and the links between government figures and the Greensill Capital finance group. Speaking on BBC Radio 4’s The Week in Westminster, Evans said present oversight standards required improvements, including the fact the prime minister’s independent adviser on ministerial interests – a post that has been vacant since November – does not have the power to start investigations. “At the moment they have to wait to be asked and that means the perception might be this is not as independent a role as it might be,” he said. “I think there’s an opportunity there to modernise this role and to ensure that they are able to allay public concerns as they arise.” Evans told Radio 4 he would write to Boris Johnson to recommend more powers be given to the independent adviser on ministerial interests. The former cabinet secretary Richard Wilson joined calls for a tightening up on lobbying and agreed the independent adviser “should be given the power to initiate investigations”. In a letter to the Times, Lord Wilson, who was cabinet secretary from 1998 to 2002, said that while lobbying was “an inevitable part of public life”, there had to be “no hint of corruption, no suggestion of cosy deals without due process, no suspicion of ‘old boy’ networks”. “Although it is difficult to legislate for morality, the Greensill and other affairs now emerging certainly suggest a need to toughen our safeguards. Greater openness is important,” Wilson wrote. He added he would “ban any former minister or senior official from lobbying government on behalf of any business that was paying them in whatever capacity”. Links between ministers, officials and businesses are under intense scrutiny after the collapse of Greensill in March and revelations about the former prime minister David Cameron’s lobbying activities for the firm. Labour has also levelled accusations of “cronyism” within the government, raising concerns about procurement during the pandemic while also calling for a full inquiry into the Greensill saga. The post of the prime minister’s independent adviser on ministerial interests has been empty since November when Sir Alex Allan resigned after Boris Johnson stood by Priti Patel in a bullying row surrounding the home secretary. A report authored by Allan had found her conduct “amounted to behaviour that can be described as bullying”.