How does the parliament exercise control over the cabinet?

Due to the so called fusion of powers within the UK political system the Prime minister has significant power over parliament. Combined the heavy whip system in force, the PMs power of patronage and a large parliamentary majority the PM is left with significant control in terms of domestic policy. However there are a system of 'checks and balences' in place which are in theory meant to balence the branches of government, i.e the legislature, executive and judicary.

Parliament can scruntise the work of the executive (PM) through committee work, primarily the work of departmental select committees. These committees scruntise the work of gov departments, ministers actions, departmental spendature etc. They can call for people, papers and records. Prime Ministers question time is another vital check on the PM. Ministers can 'interrogate' the pm and departmental ministers in these sessions. This process is hampered however by the fact questions must be submitted to the pm before hand and there have been time reductions in the Blair gov. A backbench rebellion is a further example of parliament holding the PM to account. This is where backbench MPs oppose government policy by voting against it. The extent to which this is used is determined by the majority the PMs party has in the commons e.g Jim Callaghans gov suffered 34 defeats due to a minority gov while Blair suffered only 4.