What does “Boris Johnson has a hundred and sixty MPs on his payroll anyway who were going to vote for him because they're within the government” mean?

Moments after the vote of confidence on British Prime Minister Boris Johnson results were announced live on CNN, MP David Lammy (Labor) listed results of previous (recent) votes of confidence saying this was worse, then said:

So this is a staggering amount of people. If you think about Boris Johnson has a hundred and sixty MPs on his payroll anyway who were going to vote for him because they're within the government, he's done very very poorly.

What does this mean? Are there MPs not in government? Which group numbers 160 and why would all of their votes be so absolutely certain?

Soon after that Lammy lists Johnson's problems and I think says:

...and a large amount of his MPs don't trust him.

If I've got that correct, then it seems contradictory to the 160 MPs being on Johnson's "payroll".