The UK government, regardless of which political party has been in control, has produced the current tax system, Inheritance rules are clearly stated and allow Tax Havens etc to be used.
It appears to me that currently people are just trying to make political capital and are trying to remove Cameron from office.
I do believe the company tax system has problems and should be modified for example, to stop companies, and even UK councils, from exploiting the offshore rules! this should be a priority.
Modifying the tax system is not a simple task and cannot be done in isolation. The forthcoming EU Referendum could promote a tax change!
The most important thing with tax is that it should be paid by all who obtain wealth either through earnings or through capital appreciation.
Unfortunately governments of all sides try to provide incentives for people to use their wealth to generate growth/jobs by offering incentives which can be exploited as tax incentives.
I think parliaments priority should be focused on providing the UK population with the positives and negatives of belonging in the EU together with the potential positives and negatives of leaving the EU.
The time-scale of processes that would need to be followed should we leave and what issues would need further negotiation to enable exiting.
Stop waving tax papers at each other and get to work for the UK Future.