Political parties have always been tribal bodies and, with a few notable exceptions, members generally toe the party line. That is no longer the norm. Before Brexit it would have been unthinkable for a Prime Minister to lose two major votes by 230 votes and 149 votes respectively on the main policy of her government and not resign. Conservative MPs have publically challenged and disputed that policy, voted against it and still keep the party whip. As a matter of numerical practicality that is perhaps not surprising. The Prime Minister won a vote of confidence as leader of her own party and defeated a vote of no confidence in her government but she still lost the main votes comprehensively. This is now acceptable. It may be a dangerous precedent for party managers to deal with if they are seen to tolerate the conduct of MPs who disagree with the whip, form influential groups within a party that do not accept major policy directions and regularly help defeat the government.
While some members of the Cabinet have resigned because they wished to vote against the government, others who are clearly unhappy with the way things are going have stayed on board. However with Ministers and other high profile MPs regularly writing in various newspapers from different perspectives, the concept of Cabinet collective responsibility is being well and truly stretched, as is party unity. This "speaking out" is a feature of the Opposition benches as well and may reflect the fact neither party currently reflects a position fully agreed among its members.
To add to the procedural confusion, the current Speaker seems to be taking an arguably different direction as to interpretation of certain Rules which govern the procedure of the Commons. Alleged failure to follow the Clerk to the House's advice on procedure has led to suggestions he is taking a more political role, to the detriment of the Government.
The Speaker was also moved to comment that the Government withdrawing the motion on the first attempt at holding a "meaningful vote" in December after three days of debate, when 164 members had spoken "was deeply discourteous". The usual modes of working in the House are clearly under strain.