Conservative opposition legal critic Dominic Grieve wrote in a letter to Home Secretary Jacqui Smith that Blair had placed himself above the law by trying to block an Independent Police Complaints Commission investigation into the botched subway shooting of Jean Charles de Menezes in July 2005.
Aside from that, The Independent on Sunday reported an internal inquiry was under way into some $12 million charged to 3,000 police credit cards for vacations, jewelry and luxury goods.
The force confirmed Saturday two counter-terrorism detectives had been arrested on suspicion of theft.
In a BBC interview Sunday, London Mayor Ken Livingstone denounced the political push to oust Blair as commissioner.
"We are all pretty determined we are not going to have a media campaign drive a commissioner from office ... We have never had that before and we cannot allow it," he said.