Carlaw says he would not use Boris Johnson's past commentspublished at 08:31 Greenwich Mean Time 2 December 2019
Gary Robertson says there is a third candidate, one who wrote about Muslim women wearing the niqab and used the line it was ridiculous that people would go around looking like letterboxes.
"That of course is Boris Johnson and he's at the heart of your party's problem with this, isn't he?"
Mr Carlaw replies he does not accept that.
He insists he will judge the prime minister on what he says and does as prime minister, and not on what he has said in the past.
The Good Morning Scotland presenter asks if Mr Carlaw would ever use the terms "tank-top bum boy" or "walkabout piccaninnies" or "watermelon smiles", or would he talk about Muslim women being "bank robbers".
He replies no to all these questions and further ones.