Johnson is allowed to receive legal consultations during the hearings while he would be testifying, but the lawyers cannot speak on behalf of the former prime minister and only are able to "pass notes or whisper advice to him," the report said.
The counsels may also help Johnson to prepare for the hearings in advance and draw up written submissions if necessary, the newspaper reported.
"We were trying to avoid having to do it; trying to duck it because it's so toxic. Cabinet Office staff were involved in the partygate saga. Their interest in helping him out is negative because he threw them under the bus. His leverage over everyone has slightly weakened now. But it's a convention that because he is a former prime minister, he is entitled to it," a source familiar with the matter was quoted by the newspaper.
The report added that Johnson's spokesman has declined to comment on the issue.
Johnson announced his resignation in July after continuous calls to step down following a series of revelations which showed that several social gatherings had been held at his offices throughout 2020 and 2021, flouting COVID-19 social distancing rules.
The situation was aggravated by the reports that two more parties were held on April 16 last year, right before Prince Philip's funeral, when the UK still maintained COVID-19 restrictions and was in national mourning. Johnson later apologized and said he had paid the fine issued by the Metropolitan Police.