The health secretary’s preferred candidate to become NHS Commissioning Board chair has only won endorsement from the House of Commons health committee on the casting vote of its chair.

In a pre-appointment hearing with the committee yesterday, Malcolm Grant told MPs he would not be needed in the post if the Health Bill was amended to give the health secretary greater powers over the body.

The barrister and academic, who is currently president and provost of University College London, also called the Health Bill “completely unintelligible”, said he had needed persuading to take the role and appeared surprised that the session was like a job interview.

Last night’s committee vote to endorse Professor Grant’s appointment resulted in a three-three tie, with two Conservative and one Liberal Democrat committee members in support of Professor Grant and three Labour members against. Committee chair Stephen Dorrell then voted in favour of Professor Grant’s appointment.

Three Labour members, Rosie Cooper, Grahame M Morris and Virendra Sharma, had previously backed an amendment saying Professor Grant had not demonstrated an understanding of NHS structures and issues or persuaded members that “he would provide an effective counterbalance to the executive members of the NHS Commissioning Board”.

Their amendment also noted that the Department of Health assisted Professor Grant in responding to written questions posed by the committee, was “not robust” about the advocacy role of the job, said the bill was unintelligible and “demonstrated an assumption that his appointment was already confirmed”.

The amendment voted in the same three-three split as the main vote, with Mr Dorrell’s casting vote in this case defeating it.

In the earlier hearing, Professor Grant said of the board – whose status can still be influenced by the Health Bill – that “frankly, if it ends up with the secretary of state having revised powers of direction to the board then you want civil servants to run it”.

Professor Grant said, although the bill was “completely unintelligible”, his understanding was that power would be passed to the board to bring stability to the NHS and reduce political interference.

He told MPs he had been headhunted for the role and had to be persuaded to take it on. “It’s not an obvious course for anybody who is enjoying their current job – I’m here today because I think there is a serious job to be done,” he said.

Professor Grant, whose wife of 37 years is a GP, will continue in his £376,000 a year post at UCL. However, he said his £63,000 commissioning board salary would be paid directly to the university.

He has held a series of high profile posts during the past decade including chair of the Russell Group of universities, chair of the Agriculture and Environment Biotechnology Commission and UK business ambassador. This will be his first role in the NHS, but he told the committee more than half of UCL’s activity related to life and medical sciences.

New Zealand born Professor Grant, who has been in the UK since the 1970s, told the committee he planned to retire from UCL in two years, meaning that, as his commitment to the commissioning board increased with its formal establishment, his role at UCL would wind down.

Professor Grant said he was “very strongly against” full time chairs and had seen “too many instances of the chair confusing themselves with the chief executive”. The job description for the commissioning board role suggested an eventual commitment of between four and six days a month, but will initially be two days.

He said he would seek the “most able and independently minded people he could find” to be non-executive directors and wanted to have strong “strong clinical representation on the board”.

A final decision on Professor Grant’s appointment will now be made by Mr Lansley.